eChapters

SUMMARY

Multiplicity of cropping systems has been one of the main features of Indian agriculture and it is attributed to rain-fed agriculture and prevailing socio-economic situations of farming community. It has been estimated that more than 250 double cropping systems are followed throughout the country and based on rationale of spread of crops in each district in the country, 30 important cropping systems have been identified. Cropping systems of a region are decided by and large, by a number of soil and climatic parameters which deter mine overall agro ecological setting for nourishment and appropriateness of a crop or set of crops for cultivation. Much of the Madhya Pradesh area also coincides with the rainfed semi-arid agro-ecological region and sub-regions which are upland, forested with low agricultural productivity and predominately tribal population. It would appear that over the centuries – including in recent history tribals have been inexorably moved off the better lands, into areas which from an agricultural perspective have low productive capacity and little potential for growth. Low agricultural productivity is one of the main causes of persistently high poverty rates in the state and the poor masses not only depends upon the farming system but also chosen different alternatives for their sustanability.

Sir Alexander Ogston (1880) first isolated Micrococci in pus and in 1883 he subdivided them into two groups i.e. Staphylococcus and Streptococcus. He also first proposed the name ‘Staphylococcus’ (Greek ‘staphyle’ means bunch of grapes and ‘kokkos’ means berry). Experiments of Bumm (1885), Garre (1885) and Bockhart (1887) established its relationship with human infections. As well as Nocard (1887) first isolated Staphylococcus from mastitis in sheep and found its pathogenic significance in animals.

Properties of Genus

Morphology : Staphylococci are gram positive cocci, capsulated, non-sporing and non-motile. Each coccus cell is 1µm in diameter.  They are arranged in a group or grape like cluster as cell division occurs in more than one plane. During preparation of smear and staining the cluster is sometimes broken and cocci are seen in pair or single (Fig. 1).

Staphylococcal capsule is polysaccharide in nature. The capsule can inhibit phagocytosis and helps in virulence.

 Staphylococcal cell wall contains three major components i.e. peptidoglycan (PG), teichoic acid (TA) and surface proteins.

Rivolta (1873) first described the chain forming cocci in pus collected from the equine infection. Later Rosenbach established the genus ‘Streptococcus’. Nocard and Mollereau (1887) first observed the relationship between the bovine mastitis and Streptococcus agalactiae.

Properties of genus

1. Morphology : Streptococci are gram positive cocci, capsulated, non-sporing and non-motile. Each coccus cell is 1µm in diameter.  They are arranged in a pair or chain of cells as the cell division occurs in one plane (Fig. 1). The chain formation and the chain length are variable. Streptococcus equi ssp equi is a constant chain producer, other species are not. The chain length is shorter in artificial media than natural one. Young cultures are gram positive whereas the bacteria present in the pus and older cultures in the laboratory are often stained as gram negative. 

Streptococcal capsule is polysaccharide in nature. It can be subdivided into different antigenic types (e.g. S. agalactiae, S. pneumonae). However capsules of S. equi, S. pyogenes are made of nonantigenic hyalu-ronic acids containing repeating units of glucuronic acid and N-acetyl-glucosamine. Synthesis of the polymer involves the products of three genes, hasA, hasB, and hasC, which are all in the same operon.

In 1850, Bacillus anthracis was first reported by three individuals in two different countries i.e. Delafond (who may have found them as early as 1838) and Davaine in France, Pollender in Germany. However, they could not establish the relationship between the disease and the bacterium. Absolute proof of the anthrax etiology as B. anthracis was established by Robert Koch in 1876-77. The name Bacillus anthracis was first coined by Cohn (1875) and the disease ‘anthrax’ was first named by Hippocrates (5th century B.C.). In Greek language meaning of anthrax is ‘coal’ referring to the black coloured skin or blood in affected animals.

B. anthracis organism has certain historical importance:

a)   Anthrax is the first disease identified to be caused by a bacterium.

b)   Robert Koch first isolated the organism and reproduced the disease in experimental animals. He proposed his postulates (Koch’s postulate, 1876) based on his experiments related to this organism. It later became a fundamental milestone of all microbiological works related to the infectious diseases.

c)   Louis Pasteur first used heat attenuated culture of B. anthracis as vaccine in a group of sheep in 1881 at Pouilly-le-Fort. He cultured the organism at 42-43^oC in presence of oxygen. The bacteria did not produce spores and became attenuated.

d)         First concept of bacterial antagonism was provided by Louis Pasteur and Joubert based on their work on this organism. Injection of other unidentified bacteria along with B. anthracis can prevent anthrax in animals
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The genus Clostridium belongs to the family Clostridiaceae. The genus name was originated from the Greek word ‘kloster’ means spindle, referring to their individual rod shape. Clostridia are gram positive, large, sporulating anaerobic rods (except C. piliforme which is gram negative). At present, there are more than 200 numbers of species under the genus Clostridium. Among them, 15 species can produce potent toxins and are considered as pathogenic for animals and human. The animal pathogenic Clostridia can be classified as neurotoxic, histotoxic and enteric.

In 1882, Robert Koch first isolated the organism, stained with alkaline methylene blue and vesuvin as counter stain and proved its etiologic relationship with Tuberculosis.  Ehrlich first developed acid fast stain in 1882 and used for better staining of the bacteria which was adopted by Robert Koch. Later this staining technique was modified by Ziehl-Neelsen, accordingly it is now a day known as Z-N staining. In 1890, Koch prepared a glycerine broth extract of the tubercle bacillus, known as ‘tuberculin’.

      He tried to prepare it as a curative agent; however, it was used later in diagnosis. In 1895, Johne and Frothingham described the first case of paratuberculosis in cattle, later known as ‘Johne’s disease’. Although, the causative agent was first isolated by Twort and Ingram in 1910.

            In India, bovine Tuberculosis was reported from several states since 1959 (Dhanda and Lal, 1959). Whereas bovine paratuberculosis was first reported by Nanda and Singh (1940) in Hissar, Haryana.

This family Enterobacteriaceae belongs to the order Enterobacteriales. The family comprises 25 genera. Among them there are 10 genera consistently found pathogenic for animals, birds and human. These genera are mentioned below (first 10 are consistent pathogenic).

In 1886, Escherich observed Campylobacter like organisms in stool samples of children with diarrhoea. In 1913, McFaydean and Stockman first confirmed them as Campylobacter in foetal tissues of aborted sheep. Confirmatory tests were also carried out by Smith in 1918 when similar organisms were isolated from aborted bovine foetuses. The organism was then known as Vibrio foetus. In 1963, due to certain differentiating characteristics, the organisms were separated from Vibrionaceae family and the new genus Campylobacter (means ‘curved rod’) under Campylobacteriaceae family was proposed. 

Properties of genus

1.   Morphology :  Campylobacter is gram negative, comma shaped rods specially in infected tissues and young cultures. The size is 1.5-4 µm by 0.5 µm. When two bacterial cells are found together in a microscopic field, it looks like ‘S’ or ‘wing of gull’ (‘flying seagull’). However in older cultures, the chains of organism appear as long spirals. They are motile by single unipolar/ bipolar unsheathed flagella. Motility is darting or corkscrew type, best observed by dark field microscopy. They are non-sporing. Some species contains S-layer (surface layer), a paracrystalline protein structure composed of S-layer proteins (SLPs). It is external to the outer membrane. It helps the bacteria in immune evasion.

Clinical conditions similar to Brucellosis have been described since the time of Hippocrates (450 BC). J. A. Marston first described brucellosis as gastric remittent fever in 1861 at Malta (Marston, 1861). Sir David Bruce in 1886 first isolated little coccobacillus from an infected soldier’s spleen. However he isolated the bacteria in a pure culture in 1887 and named Micrococcus melitensis (Bruce, 1889). Later the genus was renamed as Brucella in his honour. Similarly, Bang and Stribolg first isolated Brucella abortus from abortion material of a cow (Bang, 1897). Traum in 1914 isolated the Bacillus abortus suis. Presently we know it as Brucella suis. In 1953, Brucella ovis was first isolated in New Zealand (Budlle and Boyes, 1953) from the aborted material of sheep. Carmichael and Bruner in 1968 first isolated B. canis from the aborted placenta of a dog.

            In India first report of ‘Contagious abortion’ by Brucella was found from annual report of Imperial Veterinary Research Institute (presently Indian Veterinary Research Institute), Mukteswar, Uttarakhand (Anonymous, 1918). Seroprevalence of Brucellosis is reported from various states of India afterward (Polding, 1942; Sethi et al., 1971 etc.).

Pasteurella and Mannheimia species are gram negative small coccobacilli under family Pasteurellaceae. Trevisan (1887) coined the generic name Pasteurella for the first time and it was accepted worldwide. Lignieres (1900) proposed the specific name for each organism according to the species of animal host: Pasteurella aviseptica for fowls; P. suiseptica for pigs; P. boviseptica for bovines; P. oviseptica for ovines and P. leptiseptica for rabbits. Finally, Rosenbuch and Merchant (1939) proposed a single species Pasteurella multocida and it is in use till date. 

      Mannheimia haemolytica was earlier known as Pasteurella haemolytica, but because of variations in cultural, pathological and 16S rRNA sequence, it is placed in separate genus.

Properties of genus

Morphology : P. multocida is a non motile, non spore-forming short rod or coccobacillus, 0.2-0.4 by 0.6-2.5 µm in size. Repeated laboratory subcultures or cultures grown under unfavourable conditions tend to be pleomorphic and longer rods or filamentous forms appear. In tissues, exudates and recently isolated cultures, the organism shows the typical coccobacillary forms. It is a gram-negative organism and, in fresh cultures and animal tissues, gives typical bipolar staining (Fig.1), particularly with Leishman or methylene blue stain.

Lucke (1862) first described that the bluish green discolouration of surgical dressing is associated with the presence of small vibrio like organisms. Latter Gessard first isolated the organism as Pseudomonas in 1882.

Properties of Genus

1. Morphology : They are Gram negative straight or curved rod, motile by one or more polar flagella. Usually it is 1.5 µm in length and 0.5 µm in width. Longer filamentous forms are sometimes observed. The bacteria are non- acid fast, non- sporulating and uncapsulated. Pili on the bacterial surface are detected. Environmental and strains present within tissue can produce slime. The slime is composed of glycolipoprotein (GLP) and polysaccharide of LPS.
    
2. They are strict aerobe.

Classification : Pseudomonas belongs to class Gamma-Proteobacteria, order- Pseudomonadales, family- Pseudomonadaceae.  Previously Pseudomonas included two group of bacteria viz. Fluorescent group and Pseudomallei group. Recent classification system included this Pseudomallei group into a new genus known as Burkholderia. Important species of Pseudomonas are:

The genus was named after Morax who first isolated the organisms from human conjunctivitis in 1896.

Properties of genus

1.   Morphology :  Moraxella are gram negative, small rods occurring in pair (diplobacilli). The aged cultures exhibit pleomorphism, occurring in pairs or chains as short, plump rods with rounded ends. Some strains may appear as cocci. The capsule is present in fresh isolates of some species (except Moraxella catarrhalis). They are non-motile and non-sporing. Moraxella bovis contains numerous type IV fimbriae on its surface.

2.   Moraxella is aerobic, fastidious and non-fermenting in nature. However, some strains prefer anaerobic condition for their growth.    

3.   Classification : The genus Moraxella belongs to the Moraxellaceae family. Previously it was known as Branhamella. Most of the species are commensal except a few, which have disease producing capabilities. Important species are M. bovis, M. ovis, M. catarrhalis, M. boevrei, M. canis, M. caprae, M. caviae, M. cuniculi, M. phenylpyruvica.

4. Resistance : Resistance to physical and chemical agents is not remarkable. They are susceptible to desiccation and do not survive long outside the host. The beta- lactam antibiotic resistance is observed among M. catarrhalis isolates from clinical cases. This resistance is associated with the production of beta-lactamase enzyme.

Pfeiffer first isolated and described Haemophilus influenzae as a cause of human influenza (1892). So it is also known as ‘Pfeiffer’s bacillus’. Later other workers isolated and described different species of the genus Haemophilus from animals and birds. In 1903, Friedberger, a research assistant of Pfeiffer, isolated similar kind of organism from prepuce of the dogs. In 1922, Rivers described it as Haemophilus canis. In 1925, Mitchell isolated Haemophilus ovis from the respiratory tract of sheep. In 1931, Lewis and Shope first isolated and illustrated Haemophilus suis from the infected pigs. Glasser found an association between fibrinous serositis, polyarthritis in pigs (Glasser’s disease) and a small gram negative rod as early as 1910, latter became known as Haemophilus parasuis. It was first isolated by Hjarre and Wramby in 1943.  The first recorded isolation of a hemophilic organism from the birds was in 1931 by De Blieck and he called them as Bacillus haemoglobinophilus coryzae gallinarum. He isolated them from the chickens suffering a disease, now known as ‘infectious coryza’.

Taylorella was first isolated by Taylor et al. (1978) as a causative agent of contagious equine metritis (CEM), a venereal disease of horses. The disease (CEM) was first reported in the mares of thoroughbred horses in UK in 1977 breeding season (Crowhurst, 1977). Initially the causative agent was assumed as Haemophilus equigenitalis. Later on the basis of numerical taxonomic characteristics, genomic G+C contents, DNA-DNA hybridisation studies, the new genus Taylorella was proposed in 1983 (Sugimoto et al., 1983). It was approved by the International Committee on Systematic Bacteriology.

Properties of genus

1.   Morphology :  Taylorella are gram negative, small rods or coccobacilli, measuring 5-6 µm by 0.8 µm. They are pleomorphic, piliated, encapsulated, non-sporing and non-motile.

2.   They are microaerophilic (require low O₂ tension for growth), non-fermentative, and non-proteolytic in nature.

3.         Classification : Taylorella belongs to β- subclass of class Proteobacteria (whereas, Haemophilus belongs to the γ- subclass of Proteobacteria). Major important species is Taylorella equigenitalis. The genus was considered as a ‘single species genus’ for a long time. Latter in   1997, National Veterinary Services Laboratories confirmed the identity of another Taylorella species, isolated from a donkey jack (Equus asinus) in California. It was named as T. asinigenitalis. The new species has minor difference in 16S rDNA sequence (97.6% similarity), DNA–DNA hybridization (23% similarity) and (G + C) composition with T. equigenitalis (Matsuda and Moore, 2003)
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Listeria

Murray et al. (1926) first described about Listeria which was followed by Pirie et al. (1927). In India Listeriosis was first reported by Mahajan (1936) in sheep from Andhrapradesh. He recognized it as ‘circling disease’. Latter a number of reports are available from various parts of India.

Lignieres and Spitz first isolated the bacteria from the cattle with Actinomycosis like condition in Argentina in 1902. They referred them as ‘Actinobacilllus’. These findings were also confirmed by Nocard in 1902. Latter, the isolated bacterium from the cattle was named as Actinobacillus lignieresii, in memory of Lignieres. 

Properties of genus

1.   Morphology :  Actinobacillus are gram negative small rods, measuring 1.5 µm in length and 0.4 µm in width, occurring singly, in pairs or more rarely in chains. After isolation in the laboratory they may show pleomorphism varying from coccobacilli to filamentous forms. In gram stained smear they may show both bacillus and coccus form together, known as ‘morse code’ appearance (dots and dashes appearance, Fig.1). They are non-motile (both at room temperature and 37^oC), non-sporing and non-acid fast. The pili are found in A. pleuropneumoniae.

      Some of them (A. pleuropneumoniae) are capsulated. Whereas, slime layer is found in the surface of other species like A. lignieresii, A. suis, A. equuli.  This slime layer is related with stickiness of the colonies in the agar, enhanced resistance of the colonies to the chemical disinfectants, as well as, resistance of the bacterial cell to the antibiotics and desiccation.

2.         Actinobacillus are aerobic, microaerophilic or facultative anaerobic in nature. They are chemoorganothrophic having both respiratory and fermentative types of metabolism.

Cohn (1875) first observed and described a branching filamentous micro-organism in the concretions (coagulated mass) taken from a lacrimal canal, latter identified as Actinomyces israelii. Bollinger first reported the yellow granules in jaw tissues of the cattle in 1877 and established the significance of the organisms as an etiological agent. In 1878, Israel described the first human case. In 1879, Hartz observed the microscopic appearance of granules of Actinomyces infection and suggested the name Actinomyces bovis. Mosselman & Lihnaux (1890) and Wolf &Israel (1891) first isolated the bacteria in artificial laboratory media from lumpy jaw cases of cattle and human Actinomycosis, respectively.

Properties of genus

1.         Morphology :  Actinomyces are gram positive filamentous organisms with branching rods. In artificial media, short bacilli or cocci forms are also observed. During infection, they can produce yellow coloured granules (sulphur granule), commonly found in the pus as ‘opaque speck’ and are visible under naked eye (1-2 mm in diameter). The granules are usually soft and easily broken under light pressure, but they may occasionally be tough or even calcified. They are composed of club shaped bodies, arranged radially with their narrow ends towards the centre. So the organisms are also known as ‘ray fungus’. In the centre of the club, filamentous masses of gram positive organisms with some bacilli or cocci form are found. Together the club like processes and bacterial masses are known as ‘rosette’ (Fig.1). This club is composed of calcium phosphate and inflammatory debris
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The genus Arcanobacterium was first described to include the bacteria originally isolated as Corynebacterium haemolyticum from American wounded soldiers (Collins et al., 1982). The bacteria had different cell wall and lipid composition in comparison to the other members of the genus Corynebacterium. So the new genus Arcanobacterium was created.

Properties of genus

1.         Morphology : Arcanobacterium pyogenes is a Gram positive, non-motile, non- spore forming, short, rod-shaped bacterium, measuring 0.5µm by 2 µm. They are non-capsulated and do not contain any metachromatic granule. Initially (during first 18 hour of growth) the bacterial cells may show characteristic ‘V’-arrangement like Corynebacterium, latter as the growth proceeds, the organisms become granular and segmented so that they resemble small and irregular cocci (whereas, A. hippocoleae and A. pluranimalium appear to be less coccoid). The cell wall is devoid of mycolic acid, arabinogalactan unlike ‘coryneform’ bacterial group (Mycobacterium, Corynebacterium, Rhodococcus, Nocardia). Cell wall peptidoglycan is composed of N-acetyl muramic acid, lysine. Being gram positive in nature, some strains exceptionally possess fimbriae.

Corynebacterium diptheriae was first observed by Klebs in 1883 and described in details by Loeffler in 1884. So it is also known as ‘Klebs-Loeffler bacillus’. In 1888, Nocard isolated a similar type of bacteria from cases of bovine farcy. In 1894, Preisz described it completely and revealed its similarities with the diphtheria bacilli. Latter it was named as Corynebacterium pseudotuberculosis (Preisz-Nocard bacillus). Bollinger (1890) first reported C. renale from the cases of pyelonephritis in cows. Magnusson (1923) first described C. equi (Rhodococcus equi) form suppurative pneumonia of a foal.

Properties of genus

1.   Morphology

Corynebacterium are gram positive, pleomorphic bacteria ranging from coccoid to filamentous rods. The size varies from 0.5-0.6 µm by 1.0- 3.0 µm. Some of the species appear as packets of parallel cells (palisade arrangement) or show ‘V’ shaped form (Chinese letter arrangement) in the microscopic field (Fig.1and Fig.2). The cell wall peptidoglycan contains meso-diaminopimelic acid (meso-DAP). The arabinose and galactose are major cell wall sugars. Short-chain mycolic acids (corynomycolic acids, 22–36 carbon atoms) are present. This kind of cell wall structure is impermeable to the hydrophilic compounds. However, the ‘porin’ present in the cell wall sometimes helps in import of the hydrophilic substances. Mycolic acid containing cell wall helps in intracellular survival within the macrophages. Corynebacterium is non acid fast, non-sporulating, non-capsulated and non-motile bacteria (except C. aquaticum)
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Edmond Nocard (French Veterinarian) first isolated filamentous aerobic bacteria from clinical cases of ‘bovine farcy’ in 1888. In 1889, the genus Nocardia was formed by Trevisan, and the organism described by Nocard was named as Nocardia farcinica. In 1891 another similar organism (Nocardia asteroides) was isolated by Eppinger from a human brain abscess. Initially it was thought that they are the same organisms. Latter on the basis of the molecular studies their separate entity is established.

            However, 80 years later, re-examination of Nocard’s original isolate revealed two different filamentous organisms, one of which was Mycobacterium and the other was Nocardia. The cause of ‘bovine farcy’ has been subsequently attributed to Mycobacterium. Latter, it is proved that Mycobacterium farcinogenes is the actual causative agent of ‘bovine farcy’.

Dermatophilus congolensis was first described from clinical case of exudative dermatitis in cattle in Congo by Van Saceghem (Van Saceghem, 1915). It is primarily known as an animal pathogen causing acute, sub acute or chronic skin disease. The first cases of human infection with D. congolensis were reported in 1961 in four people who developed skin infection after handling an infected deer in a wildlife reserve in USA (Dean et al., 1961).

Properties of genus

1.   Morphology

Dermatophilus is a gram positive, non-acid fast, unusual bacterium having branched filaments. It follows a life cycle with different morphological features. It can be found in smears prepared from clinical samples in any form of its life cycle. Young filaments are 0.5 to 1.5 μm in diameter.  They enlarge within epidermis as they produce layers of transverse and longitudinal septations and reach 5 to 8 μm in diameter, surrounded by a mucoid capsule. The septations result in the formation of a sporangia (a kind of fungal fruiting body, sac like structure with spores) containing up to eight cocci cells. In the presence of liquid, the cocci are released and converted into flagellated motile zoospores, the infective form of the organism. It can infect the new site in the same animal or new host. These zoospores become visible in smear as parallel lines forming a ‘railway-track’ or ‘trum-track’ appearance (Fig.1). Under favourable conditions, the zoospores form germ tubes that develop into branching filaments. These filaments are the invasive form of the organism and the cycle is repeated.

Leptospira 

Antony Van Leeuwenhoek (1681) first observed the Spirochaetes under the microscope and described them. In 1833, Ehrenberg used the name Spirochaeta for free living spiral shaped organisms. Obermeir (1873) first described a Spirochaete of pathogenic significance isolated from human patients of relapsing fever. Inada et al. (1916) first isolated Leptospira icterohaemorrhagiae from human patients of Weil’s disease. In 1980, Nogochi proposed the name Leptospira.

      In India, Taylor and Goyale (1931) first reported Leptospira from human patients suffering from jaundice in Andaman Islands (Srivastava, 2006). Ayyar (1932) first reported Leptospira from dogs in Chennai city. 

Properties of genus

1. Morphology : Leptospira are gram negative, spiral shaped organisms with hooked ends. Length varies from 6-20 µm with 0.1-0.2 μm diameter (Fig.1). They have a typical double membrane covering. The cytoplasmic membrane and peptidoglycan cell wall are closely associated and are surrounded by an outer membrane. Two periplasmic flagella (endoflagella) are found within the cell and are responsible for the motility. No flagella are present as extracellular appendages. One end of the flagella is attached with the pole of the bacterial cell by insertion disc. Other end extends towards the centre of the cell and may overlap the flagella coming from the opposite end. The endoflagella consists of a solid inner core surrounded by tubular sheaths. The FlaA and FlaB proteins constitute these flagellar sheath and core, respectively.

Properties

1. Bacteroides, Dichelobacter and Fusobacterium are major gram negative anaerobes isolated from human and animals. Other gram negative anaerobes are listed below (Table-1).

       2.   They are tolerant to oxygen in comparison to strict anaerobes. They do not die after oxygen exposure

       3.         They naturally inhabit the intestine and mucosal surfaces of human and animals. Majority of them are opportunistic pathogens. Often they cause mixed bacterial infection along with aerobes. Aerobes remove oxygen and create an anaerobic condition favourable for their growth. Aerobes may also supply other growth requirements. For e.g. Porphyromonas asaccharolytica requires vitamin K for its growth, supplied by another bacterium, not the host.

The name Mycoplasma is originated from the Greek word mykes (fungus) and plasma (formed). It was first used by Albert Bernhard Frank, a German Biologist in 1889. He thought it was a fungus. An older name for Mycoplasma was Pleuropneumonia-Like Organisms (PPLO), referring to organisms similar to the causative agent of contagious bovine pleuropneumonia (CBPP). It was later found that the fungus-like growth pattern of M. mycoides is unique to that species. It was first isolated in 1898 by Edmond Nocard and E. Roux from bovine lungs. Whereas, Mycoplasma pneumoniae was considered as a virus previously. Eaton and his co-workers cultured the causative agent of human primary atypical pneumonia (PAP) or "walking pneumonia." It was known as "Eaton's agent." In the early 1960s, Leonard Hayflick, in Philadelphia, was first to isolate and cultivate the causative agent of primary atypical pneumonia and identified the agent as a Mycoplasma and named it Mycoplasma pneumoniae.

History of Rickettsial infections went back to 16^th century and it has long been associated with famine and war. Thus Rickettsial infections played a significant role in the history of Western civilization. Epidemic typhus had major impact to decide over the outcome of several wars. This epidemic alone killed or caused great suffering to over 100,000 people in the two World Wars.  However, the causative agent was not determined until the early part of the 20^th century. Rocky Mountain Spotted Fever (RMSF) was the first detected Rickettsial infection as early as in 1896 in Idaho Valley, USA.  It was originally known as ‘Black Measles’ because of its clinical appearance in the form of characteristic spotted rash appearance throughout the body of the patients. Howard Taylor Ricketts, an American pathologist for the first time described the causative agent of Rocky Mountain spotted fever and was able to isolate it in the laboratory animals during 1902-1909. He was a dedicated scientist and, on several occasions, injected himself with a pathogen for experiment. The causative pathogen of Rocky Mountain spotted fever, Rickettsia rickettsii was named after him. Later, the family Rickettsiaceae as well as the order Rickettsiales was named after him. Ernest William Goodpasture, an American pathologist and physician, invented the methods of isolation and culturing the rickettsial pathogens in chicken embryos and fertilized chicken eggs.

The word ‘chlamydia’ comes from the Greek word ‘chlamys’ which means, “cloak draped around the shoulder”. This describes how the intracytoplasmic inclusions caused by the bacterium are “draped” around the infected cell’s nucleus. Chlamydia was first discovered by a Czech zoologist and parasitologist, Stanislaus von Prowazek in 1907 in Berlin, but scientists believe it was actively infecting people for centuries before its discovery. Because the symptoms of Chlamydia are similar to some other infections it was not identified as a sexually transmitted disease. Originally, because of its structure it was thought to be a virus. In 1963 it was recognized as bacteria rather than a virus.

Properties of genus

           They are poorly stained by Gram’s stain. Chlamydiae are readily stained by Castaneda (blue in appearance), Giemnez and Macchiavello (red in appearance) methods. However, Giemsa staining is preferable to stain the inclusions (Chlamydial micro colony) in the cell culture. Inclusion bodies of the Chlamydiae are basophilic in nature. Again, the staining of the inclusion bodies may differ depending on the species. In C. trachomatis, the inclusion bodies contain glycogen matrix and can be easily stained with iodine solution.

Introduction to Swine Farming

World pig population in the year 2007 was 918,278,000 when the pig population in India was 14,000,000. The per head agricultural land holding is decreasing continuously because of a high rate of increase in population leading to excessive pressure on land. This lower land holding per person leads to lowered production per person forcing people to move to urban areas for better incomes. Excessive population pressure on urban areas itselves has its own demerits and limitations. To prevent this drift of village people to the urban areas they should be encouraged to adopt agriculture based professions which give the villagers a good return in short time span. Swine industry provides the same opportunities to villagers who can get better income with a minimal investment in short time intervals. In India for varied reasons the swine industry is not much developed. The breeds yield less and also the littre size is small in comparision to the better breeds available in many parts of world. In India, the desi swine survives on garbage and looks very unhygienic. Thus, most of the people in India feel uncomfortable to consume swine. Indian swine industry has a great potential but needs attention with respect to raising of better productive breeds with lesser cost for hygienic feeding and management.

            Pig is mainly reared for meat, skin and manure. Growing pigs for meat is little different from other production processes because here the daily live weight gain relates to the daily feed supply and the efficiency of output production depends upon the total quantity of input (feed).

(I)  Management of Swine

Since early days, cattle, sheep and goats accompanied human beings where ever they migrated but it is not the same with swine because of its rearing in unhygenic conditions. Some communities started avoiding swine because of the foul smell from pigs and slowly it entered into the religious life of Muslims and Yashdies.

            In China since 4900 BC and in England before 800 BC swine production scripts are found in majority in these two countries and at present these countries are leading in swine production. Swine growth is very much influenced by the method of keeping and rearing them and that is why its managemental practices should always be given high priority.

Reproduction

The female piglet attain maturity in 6-7 months of age and has a weight of 60-80 kgs. Males take more time to attain adolesence. The breedable age of a female is 8-12 months when it has a weight above 100 kgs. Its heat period is for 2-3 days. It may conceive by artificial insemination after 2-3 days of heat. The gestation length is 114 days. Weighing may be done after one month of age. Females generally give birth to 6-10 young ones at a time. If more young ones are born, than there are increased chances of death of the young ones.

(I)  Structure

The swine is an omnivorous animal because if can eat both vegelables and meat. But generally they prefer the vegetarian diet over the carnivorous diet. Pig is a simple stomach animal with double hoof. Different type of pigs are found as Sus indicus, Sus vittatus, Sus scrofa and  Suis domesticus.

            At the first instance, the skeleton of pig looks smaller than its original size. The main reason of this is feeding and nutrition of the animal. The pigs are kept indoor, provided less exercise and artificial feeding that leads to fattening of animals (pigs). The other reason for the undersized skeleton in pigs is that as compared to other animals the bone density of pig is more and they are very nicely arranged, that is why they are much stronger. The skull of the pig is triangular, long towards mouth, frontal bone is large and strong.

            The jaw has teeth, they use it for tearing and chewing of objects (feed). The temporary and permanent dental formula of pig is follows:

(I)  Breeds

Basically swine is a clean animal and in our country, mainly, poor people  are rearing them with the least available infrastructure and poor quality feed, usually garbage, and that is why swine  are forced to take garbage as a feed (Fig. 23). With good food and shelter, they can give birth twice a year with better productivity. Even 8000- 9000 years back swine stood at 3^rd position for being reared by humans after cattle and sheep. Swine comes under phylum Chordata as they have vertebral column and their class is mammalia. They come under Artiodactyla for being ungulate animals. Swine comes in Swede order and their species is swiss. They have 3 subspecies. The domesticated subspecies comes under Swede domesticus and wild pigs comes under Swede vitatus and Swede scrofa. In India there are 4 breeds of pigs. Wild, desi, exotic and crossbred.

(I) Digestion of Feed

In feed, carbohydrate is the main nutritive substance which is in the form of insoluble large particles. For intestinal absorption by blood and lymph, it is necessary to be digested as small and simple particles. For example, carbohydrate found in the form of starch or glycogen is not absorbed as such and is only absorbed when it is converted into the simple soluble monosaccharide form. Similarly, proteins present in the feed are also not absorbed untill they are digested into simple forms of aminoacids (Fig. 27, Fig. 28, Fig. 29, Fig. 30). Piglets are exceptions, as the newly born piglets obtain colostrum from their mother. Colostrum is rich in gamma immunoglobulins. This immunoglobulin is abosrbed as such without digestion by pinocytosis. It gives immunity to save the new piglets from many diseases. For this reason, colostrum suckling is necessary for new piglets. The process of pinocytosis occur only few days after birth and it  stops after some time. Fat occurs in the form of triglycerides in the feed. For absorption of the fat, it is necessary to be converted into its simple forms such as glycerol, free fatty acids or in the form of monoglycerides.

(I)  Deficiency Diseases

Mineral and vitamins, in adequate quantities, are essential in the diet of all animals. Many diseases occur due to deficiency of mineral and vitamins. Mineral and vitamins are more necessary in pigs due to their higher growth rate. It is normally seen that when pigs are reared on self made rations, they suffer more with the deficiency of one or more mineral and vitamins. Thus, it is necessary to introduce extra mineral and vitamins in the pig ration. If it is not done, its growth rate and body weight do not increase in proper ratio. The excess and deficiency of one mineral depends on quantities of other minerals present in the ration. It is frequently seen that pigs suffer from deficiency of more than one mineral and vitamin but some time pigs suffer from deficiency of one substance and excess of the other substance, so a balanced ration- with appropriate proportions of various mineral and vitamins- is necessary. Many times it is seen that some infectious diseases increase the necessity of mineral and vitamins in the body. This may cause deficiency of mineral and vitamins in the body and the animal may not recoup.

Following are the description of these symptoms and their prevention.

Pig Production on Scavenging

Pig farming has become a profitable enterprise since it possesses many economic traits e.g. high prolificacy, faster growth rate, shorter generation interval, low cost of rearing and high dressing percentage with better feed conversion efficiency. Pigs give quick return, convert inedible feed into valuable products, require less labor, adopt most types of farming systems, aid soil fertility, supplement other enterprises, etc. It is still considered as backward profession and unorganized rearing largely dominates the sector, and it is primarily in the hand of poor, landless and weaker section of society.

(I)  Slaughter and Preservation of Swine

Clean meat production from animals has been a difficult task since ancient times. Now it has become easier due to the joint efforts of Veterinarians and progressive animal owners. For clean meat production, with healthy animals, it is essential that care is given to their better management, better breeds, good ration and arrangements for preventing diseases are made. Meat from diseased animals is of inferior quality and unfit for human consumption.

            Meat is a very useful edible material, which is used for its high nutritive value with a good taste. Due to these nutritive elements, many microorganisms come in contact with the meat and they may contaminate it and change its natural structure and composition. As a result it produces many types of toxic and bad odour substances.

            Meat has an important place amongst human foods. Meat has many pecularities for which it is used in many parts of the world and by people of different religions. Many people prefer meat because of its better taste and/or odour. Often, it is observed that people consuming meat do not prefer vegetarian foods. The active consumer always gives more importance to the nutritive elements in meat. And at the time of bying meat, they prefer taking complete meat.  Allmost in all countries of the world, few selected and common animal species are slaughtered for meat production.

Swine Marketing

The animal population in India is nearly 14 millions which is increasing day by day. The importance of animals in Indian Economy cannot be neglected. The economic benefit from animals is 26% of the total benefit from agriculture. Agricultural farming is not possible without animals. In agricultural profession, animals have an important role. In our country, crores of small and marginal farmers and agricultural labourers depend for their life on animals for their livelihood. Poor animal wealth is not a good symptom for a country.

Till today the work which is done on animal wealth by economists and marketing specialists is only limited. Economic and marketing studies on meat producing animals in our country is very less. Pigs are normally reared for meat purposes. Pigs are mostly untouched from this type of research on economic and marketing aspects. Pig population in our country is nearly 12 millions, which is 2.5% of total animal population in India.

Due to lack of studies, it is not possible to give any statement about correct situation of marketing and capacity of pigs.

Commonly used terms in swine husbandary

Angier, Natalie (2009-11-09). “Pigs Prove to Be Smart, if Not Vain”. The New York Times (New York, New York, US: The New York Times Company).

Anonymous 2002-03. Annual Report of Animal Husbandry and Veterinary Department, Directorate of Animal. Husbandry and Veterinary Department, Government of Mizoram, Pp 8

Broom, Donald M.; Hilana Sena, Kiera L. Moynihan (2009-11). “Pigs learn what a mirror image represents and use it to obtain information”. Animal Behaviour 78 (5): 1037-1041.

Burkholder JoAnn; Bob Libra, Peter Weyer, Susan Heathcote, Dana Kolpin, Peter S. Thorne, Michael Wichman (2007) Impacts of Waste from Concentrated Animal Feeding Operations on Water Quality. Environ Health Perspectives. 115:308-312.

Chandrashekhar Sahukar. (2000). Piggery India Year Book, pp. 343-347.

Christianson, L.L, Bane D.P, Curtis S.E, Hall W.F, Muehling A.J, and Riskowski G.L. 1989. Swine Care Handbook for Pork Producers Using Environmentally Controlled Housing. Des Moines: National Pork Producers Council.

Crucik Shank, R et al (1965). Medical Microbiology, ELBS, London.

Curtis, S.E., et al. 1988. Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. Champaign III, Consortium for Developing a Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching.

Dalton, C. and. Kilgour R.1984. Livestock Behaviour; A Practical Guide. Granada Publishing, Lt., Frogmore, St. albans, Herts, U.K.

Daszak et al (2000). Emerging Infectious Diseases of Wildlife — Threats to Biodiversity and Human Health. Science Vol 287 pp 443-449

Delgado, C., Rosegrant, M., Steinfeld, H., Ehui, S., Courbois, C., 1999. Livestock to 2020. The next food revolution. Food, Agriculture, and the Environment Discussion Paper28. IFPRI, FAO, ILRI

DeShazer, J.A and ONil erhults D.G.1982. Energy Demand in Livestock Production. Livestock Environment, Proceedings of 2nd International Livestock Environment Symposium. American Society of Agricultural Engineers, St. Joseph, MO.

Donham K. (1998). “The impact of industrial swine production on human health”. In Thu K, Durrenberger E. Pigs, Profits, and Rural Communities. Albany, NY: State University of New York Press. pp. 73-83.

Eastman, Wilbur F. The Canning, Freezing, Curing & Smoking of Meat, Fish & Game, Garden Way Publishing, 1975, ISBN 0-88266-045-4

Embog, H.D. et at (1996). How the Danish surveillance system for Salmonella has influenced the microbiological quality of swine carcase meat. Proc. Int. Pig. Vet. Soc.14:714.

FAO (1983). Integrated crops and livestock in West Africa. Animal Production and Health paper. Rome, No. 41. Foodand Agriculture Organisation of the United Nation.

FAO (1998a). Farm Animal Genetic Resources: Biodiversity for food and agriculture. Food and Agriculture Organisation of the United Nation.

FAO (1998b). Local animal breeds still threatened by extinction, No. 4. Food and Agriculture Organisation of the United Nation.

FAO (2001). Bulletin of Statistics. Vol.2, No.1. Food and Agriculture Organisation of the United Nations.

INTRODUCTION

Modern agriculture relies more on monoculture, which is highly energy intensive and has a narrow genetic base. This has disturbed the normal ecosystem and sometime results in disease epidemics. The problem becomes much more serious in case of soil borne pathogens, as soil medium is a highly complex living system and is also the habitat of many micro organisms including the pathogens whose activities are influenced by interaction in it. Many serious plant diseases are associated with soil-borne plant pathogens, which cause root rot, crown rot, damping off, blights, fruit decay and wilts in field and horticultural crops. Soil borne plant pathogens, which are most tricky and challenging ones, cause sustainable economic loss. Many important fungal pathogens reside in the soil and infect roots of crops often causing significant yield losses. Soil-borne diseases result from a reduction in biodiversity of soil organisms.

INTRODUCTION

Rhizoctonia solani Kuhn (teleomorph: Thanatephorus cucumeris (Frank) Donk is cosmopolitan in soils. It is a destructive plant pathogen with an almost unlimited host range. The fungus inhabits in soils and causes damping-off of seedlings, root, crown and stem rots, and occasionally foliar blight (Baker, 1970). R. solani is an important symbiont with the saprophytic seedling stage (protocorm) of many orchids (Warcup, 1985). It aggressively colonizes organic matter and is one of the fastest growing fungi. According to available information, the isolates of R. solani possess the following-characteristics (Plate 2.1).

INTRODUCTION

All plant species grown on this universe are attacked by insect-pests and diseases, resulting huge yield losses in agriculturally important species. Among diseases, extensive yield losses occurred due to soil borne fungal plant pathogens. Soil borne fungal pathogens infect roots or stem bases, their dispersal and survival stages are primarily confined to the soil. Although many soil pathogens may also produce air or water dispersed spores which results in long distance dispersal. Soil borne fungal diseases are specifically those diseases where the soil borne fungi has the capacity to survive in soil for long periods in the absence of their hosts, or survive in the soil outside of seed or host residues, but infection and symptom expression are confined to the subterranean organs of the plant. Soil borne fungi may be divided into two classes: i) The  soil inhabiting fungus which is characterized by its ability to survive indefinitely as saprophyte (e.g. Rhizoctonia, Sclerotium) and ii) The soil invading or root inhabiting fungus which is characterized by an expanding parasitic phase and a declining saprophytic phase after  the hosts death.

INTRODUCTION
 
The form genus Sclerotium was described by Saccardo (Saccardo, 1913) to include fungi that produce sclerotia and had sterile mycelia. Several fungi were inc1uded in this genus, and all were characterized by production of small, dark brown or black spherical sclerotia that were internally differentiated into a rind, cortex and medulla. Several plant pathogenic fungi with this sclerotial type and with no known sexual or conidial state were placed in the genus Sclerotium. However, as the teleomorphic states were discovered, affinities to the Basidiomycotina (Punja, 1988) or Ascomycotina (Krause and Webster, 1972) were established for some members of the form genus.

INTRODUCTION

Biological control involves the suppression of pests/organisms with other organisms.  It is an eco-friendly method for management of plant pathogens which can be done exploiting the fungi (Ampelomyces, Trichoderma, Coniothyrium, Candida etc.) or bacteria (Agrobacterium, Bacillus, Pseudomonas and Streptomyces) from rhizosphere,  as well as phylloplane and endophytes (Jayaraman and Verma, 2002). The rhizosphere microfloras are predominantly composed of gram negative pseudomonads.  The fluorescent pseudomonads constitute a large proportion of the rhizosphere microflora presumably due to their nutritional variability being able to use a large number of organic substances (Stolp and Gadkari, 1981). However earlier workers used fluorescent pseudomonads extensively they now prefer Bacillus sp. due to their spore forming ability and heat tolerance which make its formulation easier.

INTRODUCTION

Throughout the history of agriculture, humans have struggled to reduce the adverse effects of plant disease on their crops. Early agriculturalists realized the benefits of cultural practices such as crop rotation and the use of organic soil amendments in promoting plant productivity. It is now well established that many of these effects are achieved by promoting the natural microbiological processes that keep plant disease in check. Cultural practices were mainstays of traditional agricultural systems and still provide the primary approaches for management of many soilborne diseases today. For example, disease suppressive soils, into which pathogen(s) can be introduced without causing the expected levels of disease severity, can result from alterations in cropping patterns or other cultural practices. Recently,

INTRODUCTION

Wheat has served as a source of staple food to the mankind since times immemorial. The production of wheat in India got a fillip after green revolution. Wheat production in India has increased by over ten times in the past five decades and India has become the second largest wheat producer in the world. Today, wheat plays an increasingly important role in the management of India’s food economy (Gandhi, et al., 2001). Wheat, primarily the winter cereal of Indo-Gangetic plain, is a major contributor to the agricultural economy of India, occupying nearly 25.9 m ha area with 71.8-mt production (Anon., 2003).

India is also second most populous country with one billion people. Demographers indicate that by 2012 India’s population will reach 1.2 billion. With this ever increasing population, there is also an increase in the demand for food grains. Depending on the rate and nature of economic growth and given the population growth rate about 4 or more per cent, annual rate of growth in the demand for wheat is likely to increase in the near future.

INTRODUCTION

In India, temperate fruits are grown successfully at locations above 3000 feet mean sea level in hilly areas of Himachal Pradesh, Jammu and Kashmir, Uttranchal, Sikkim, parts of North Eastern states like Assam, Arunachal Pradesh, Nagaland, Meghalaya etc. Mount Abu hills of Rajsthan and Nilgiris of Tamil Nadu also provide suitable agro-climatic conditions for growing some temperate fruits. Apart from apple; pear, peach, plum, apricot, cherry, almond and walnut are major temperate fruits being grown over 3.38 lakh hectares of area and play pivotal role in the economy of hilly farmers whose land is not otherwise considered suitable for traditional agriculture. They contribute about 11.5 percent of total area under fruits in the country, yet production is only 5 percent of the total. Incidence of many fungal, bacterial and viral diseases in these fruit crops is a major impediment in their successful cultivation and soil borne pathogens are of foremost importance and are responsible for premature death of the trees in the orchards. Amongst these, white root rot, collar rot, seedling blight, crown gall, hairy root are the major constraints which can cause as high as 40 percent damage in certain situations (Sharma and Sharma, 2001). Threat from the replant problem is causing concern due to its negative effect on the establishment of replanted sites due to soil sickness.

INTRODUCTION

‘Wilting’ is a broad terminology used by Plant Protection Scientists.  Any disturbance or damage to the normal physiology of the plant leads to ‘wilting’ of plants.  Wilting in cotton is attributed to many factors and it is necessary to single out the actual cause for wilting before suggesting any remedial measure (Kannan, 1991).
Wilting in cotton could be due to any one or more factors as indicated below:

INTRODUCTION

The fine feeder roots of many vascular plants are invaded by specific nonpathogenic fungi forming a distinct morphological unit known as mycorrhiza (In Greek, Mykes mean mushroom or fungus, rhiza mean root). Physiologically mycorrhiza represents a case of symbiosis.

The term mycorrhizae were coined by a German botanist Albert Bernard Frank in 1885 which literally mean “fungus-roots”.  Mycorrhizal fungi form a symbiotic association with agricultural and horticultural crops in addition to certain tropical tree species.
Mycorrhizal fungi are broadly classified in to two groups:
1) Ectomycorrhizae  
2) Endomycorrhizae.

INTRODUCTION

Burgeoning human population and its elevated living standard have greatly demanded more agricultural production. But unfortunately agricultural crops suffer deadly due to many biotic and abiotic stresses. Of biotic stresses, phytonematodes, the hidden enemies of crops are real threat to successful and profitable cultivation of agricultural crops (Plate. 11.1). These, endoparasitic nematodes, Meloidogyne spp. and Heterodera spp., are mainly dreadful causing wrecking havoc to agricultural scenario. Chemical control of these, tiny parasites created residue, resistance, resurgence, hazardous and pollution problems to the growers as well as soil and atmospheric environment. To overcome these hazards, efforts are being made to go for non-chemicals means of nematodes management strategies in crops. Hence, a research work carried out on management of these endoparasitic nemas particularly Meloidogyne spp. and Heterodera spp., through non-chemical methods is reviewed in subsequent status.

INTRODUCTION

In arid and semi-arid regions of India, besides weather aberrations, diseases caused by certain soil-borne pathogens are responsible for low productivity of agricultural crops. In addition to losses caused in annual crops, occurrence of these diseases in forestry takes away a major share. Because of the requirement for free water, diseases of aerial plant parts are much less common than those involving roots when plants are grown in dry regions where humidities are low and rains are infrequent and/or of short durations. Under these conditions, pathogens like Macrophomina phaseolina, Ganoderma lucidum, Cylindrocarpon lichenicola, Neocosmospora vasinfectum, Sclrotium rolfii and species of Fusarium (F. oxysporum, F. solani, F. equiseti, etc.) cause root rots and wilts in many commercially valuable and perennial plants.
Certain agro-climatic factors are attributed for the development of few specific diseases caused by soil-borne plant pathogens. Low organic matter, small microbial population coupled with poor moisture retention capacity of soil favour survival and multiplication of soil-borne pathogens (Fig. 12.1).

INTRODUCTION

Fungi naturally present in soil and rhizosphere of various crops serve as potential biological control agents of various plant pathogens. Species of fungi occurring in the genus Trichoderma have gained significant importance for use as agents for control of several diseases of cultivated crops. The last decade has witnessed a tremendous break-through in the research efforts on biological control of plant diseases in India especially by using species of Trichoderma and Gliocladium. Several economically important plant diseases of a variety of crops were effectively managed by using Trichoderma based biofungicides.

The work on biocontrol of pigeonpea wilt by Bacillus subtilis by Dr. R S Vasudeva and his associates, published as a series of papers in Annals of Applied Biology during 1950 to 1965 can be considered as a starting point for Indian work on biological control of plant pathogens (Mukhopadhyay, 1994).