eChapters

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.

Pasteurella and Mannheimia species are small (0.2 x 1-2 μm) non-motile, Gramnegative rods or coccobacilli. They are oxidase-positive facultative anaerobes, and most species are catalase-positive. Although non-enriched media will support their growth, these organisms grow best on media supplemented with blood or serum. They usually remain viable for only a few days on culture plates.
Some species, such as Mannheimia haemolytica, Pasteurella trehalosi and P. aerogenes can tolerate the bile salts in MacConkey agar. In smears from infected tissues stained by the Giemsa method, pasteurellae exhibit bipolar staining.
The family Pasteurellaceae comprises five genera, Actinobacillus, Haemophilus, Mannheimia, Pasteurella and Lonepinella. These genera share a number of common features and some organisms have been reclassified within these genera following deoxyribonucleic acid hybridization studies and 16s rRNA sequencing.
The pasteurellae are small (0. 2 μm by up to 2.0 μm), Gram-negative rods or coccobacilli. They are nonmotile,non-sporing, facultatively anaerobic, fermentative(except for P. anatipesrijer), oxidase-positive andcatalase - positive (except for P. caballi). Althoughunenriched media support their growth, they grow beston media supplemented with serum or blood.
Recent Changes in Nomenclature
Previous name Present name
Pasteurella ureae Actinobacillus ureae
Haemophilus avium Pasteurella avium
Pasteurella pneumotropica Pasteurella dogmatis
(Henriksen biotype)

9.1 Introduction
The term “pasteurisation” is derived from the Frenchman Louis Pasteur, who demonstrated that the preservation of wine was enhanced by heating it to a temperature of 122 to 140 °F, which eradicated spoilage organisms. This occurred between 1860 and 1864. The utilisation of this procedure resulted in the development of a new term, “pasteurisation,” which rapidly acquired popularity in the field of technology. Although Louis Pasteur was a pioneer in the discovery of the use of thermal treatment to preserve wine, the process of pasteurising milk was initially attributed to Dr. Soxhlet of Germany in 1886.

9.2 Heat treatment of milk
In the context of market milk, pasteurisation is currently defined as the process of heating each component of milk to a minimum of 63°C for 30 minutes, 72°C for 15 seconds, or any other temperature and duration that achieves the same level of effectiveness. Equipment that has been certified and functions properly is required for this process. The milk is promptly chilled to a temperature of 5°C or lower after the pasteurisation procedure.

1. Introduction

Milk is a source of abundant nutrition has been a vital part of human civilization since prehistoric times. However, because of its perishable nature, it requires immediate processing to improve the shelf life and safe consumption .With the advancement of processing techniques in dairy and food processing, there is a widespread option being utilized to improve the milk shelf life byeither thermal technologies (pasteurization, sterilization, and ultra-high temperature) or nonthermal technologies (high pressure processing, high pressure homogenization, pulse electric field and ultra sonication). Still, pasteurization and sterilization are the two foremost process is used for milk industries. Pasteurization is the thermal inactivation of microorganisms at temperatures below100°C that enhance the safety and quality of milk and milk products and extends the shelf life to an extent. 

Introduction
Patchouli is known as patcholi in Hindi, patche tene in annada, patchapan or patcha in Marathi, patchilla in Malayalam, pacchilai in Tamil. It is a hardy perennial herb well-adjusted against the hot and humid climatic situations. Patchouli is an aromatic herb of immense importance due to presence of essential oil extracted from shade dried leaves. It possessed a powerful sweetness and spicy fragrance. Patchouli has tremendous business potential owning to its unique fragrance properties in the global market. Its oil easily blends with other essential oils giving strong base as fixative properties in preventing evaporation and promoting tenacity. Worldwide, Indonesia is considered as the chief patchouli oil producer.
Origin
Pogostemon cablin Benth. is natural to Philippines but also found growing wild in many countries of South Asian region. The word ‘cablin’ is derived from ‘cabalam’, a local name in the Philippines. Presently, it is not only cultivated on commercial scale in India but also in Indonesia, Singapore, China, Malaysia, Brazil, West Africa, Seychelles, Vietnam and West Indies.

10.1. Origin and distribution

• Native of Philippines

• Grows wild in Malaysia, Indonesia and Singapore.

• Natural habitat extends across Paruguay, Penang, East and West Indies, sub-tropical Himalayas and Deccan peninsula.

• Introduced into India by Tata Oil Mills

• Cultivated in Bangalore and coastal areas of South India, Bengal, Odisha and Assam.

10.2. Economic importance

• Oil of patchouli is called patchoulol. Oil contains benzaldehyde, eugenol and cinnamic aldehyde etc.

Leaf webber: Syngamia abruptalis :Pyralidae
 
Caterpillars feed extensively on tender foliage leaving veins alone and the growth of the plants are affected.

Leaf roller: Psara stullalis: Pyralidae

Larvae of these small moths are also leaf Webbers and rollers, and rolls the leaves and feed inside causing browning and drying of affected leaves. Inspect the crop for the pest incidence and remove the initial attacks systematically.

Scientific name: Pogostemon cablin Benth.
Family: Lamiaceae
Patchouli (Pogostemon cablin) is a perennial herb native to Southeast Asia, commonly found in India, China, and Indonesia. This fragrant herb has been used for centuries in traditional medicine, perfumery, and spiritual practices. Patchouli leaves are ovate-shaped, with a rough texture and a powerful, earthy fragrance. The leaves are steam-distilled to produce a rich, dark green essential oil with a distinctive scent. Patchouli is known for its anti-inflammatory, antiseptic, and antifungal properties, making it a popular ingredient in aromatherapy, skincare, and insect repellents. In India, patchouli is considered a sacred herb and is often used in traditional Indian medicine, Ayurveda, and Hindu rituals and ceremonies.
Origin and distribution
Patchouli, a native plant of the Philippines and Indonesia, has been extensively cultivated in various regions. In Indonesia, patchouli cultivation began in Aceh, Sumatra, and later expanded to Java. In India, it is primarily grown in the coastal areas of Tamil Nadu, Karnataka, Assam, and West Bengal.

Technology transfer is an important commercial tool for leveraging and optimizing the value of intangible assets in the present era of globalization which has deepen the process of integration of the economic resources including the free movement of goods, merchandise, services, capital and intellectual property rights. This economic integration is facilitated by a legal framework of World Trade Organization (WTO) under various agreements including the Trade Related Aspects of Intellectual Property Rights (TRIPS). There are other International Institutions i.e., World Intellectual Property Organization (WIPO), World Customs Organizations (WCO) and United Nations Conference on Trade and Development (UNCTAD) to regulate and provide guidance for the protection and enforcement of IPRs. The present global economy is geared and triggered by knowledge and almost 80 % of the global wealth comes from knowledge based intangible assets and helps optimization of the limited global resources. Technology transfer is a tool for leveraging the value of IPRs and also for sharing knowledge around the world. Knowledge is weightless and in today’s era, knowledge is driven by Information and Communication Technology (ICT) which adds to productivity in all aspects of economic life.

The term “Technology transfer” broadly connotes transfer of knowledge from one legal entity to another legal entity within and outside the national territories of the legal owner of the Patent holder at a consideration, known as license fees or technical fees or royalty. This may happen as a part of Foreign Direct Investment (FDI) or as a part of pure technological collaboration. In other words, Transfer of Technology (TOT) and Technology Commercialization allows the transfer of the technology by a patent holder to a user for further development and exploitation of the technology into new products, processes, applications, material or services. Patent provides an exclusive right to the patentee to exclude others from using an invention without his consent and the technology transfer is the process to include the licensee as the legal user without infringing the rights of the patentee. The exclusive right granted to a patentee is the right to prevent others from making, using, selling, or distributing the patented invention without his permission. The technology transfer allows the user to use the patented technology with the consent of the patent holder.

Section 4.1 Patent Application Process in India
4.1.1 Introduction
India’s patent system is governed by the Patents Act, 1970, as amended by the Patents (Amendment) Acts of 1999, 2002, and 2005, and is administered by the Office of the Controller General of Patents, Designs, and Trade Marks (CGPDTM). The Act aligns with the Trade-Related Aspects of Intellectual Property Rights (TRIPS) Agreement, ensuring compliance with global standards. For inventions in modern biotechnology, the patent application process in India involves a rigorous examination of novelty, inventive step, industrial applicability, and statutory exclusions, particularly under Sections 3(b), 3(c), 3(d), and 3(j).
 4.1.2 Who Can Apply?
Under Section 6 of the Patents Act, a patent application in India can be filed by:
• The true and first inventor,
• An assignee of the inventor,
• A legal representative of a deceased inventor.
In the case of collaborative research or industrial research programs, both academic institutions and corporate entities can apply jointly.

Abstract

Patent infringement is the act of unauthorized making, using, offering for sale or selling any patented invention within the India. In case of patent infringement it is necessary for the patentee to compare the claims granted to him with the allegedly infringing product an check whether there is an infringement – whether the infringing product falls within the scope of the claims of the patent. In such a case the patentee may sue for relief in an appropriate court. The patentee may ask for permanent injunction and damages on account of the infringement. It is the crusade of the inventor asserting his rights against an infringer and the law recognizes the importance of this right; because, without such positive and assertive rights, industrial progress would be hard to come by

Abstract

Patent is a monopoly right which is granted by the Government to the applicant for the full disclosure of an ‘invention’ which is ‘new’, ‘inventive’ and ‘industrially applicable’. Thus, before filing a patent application, the inventor must be sure that the work done by him is new and inventive. Further, during the examination of the patent application, it is required to be verified that the invention claimed in the disclosure/specification is new, inventive and industrially applicable. Since the search for the ‘Novelty’ of the invention is carried worldwide, it becomes all the more important for the inventor and the examiners to search for the prior art thoroughly. Searching for the prior art (i.e. state of the art) across the globe in around millions of documents both patents and non-patent documents, is like ‘searching a needle in the haystack’. However, by using proper keywords and classification techniques, it is possible to arrive at the closest prior art available. Each patent application is classified by the Indian Patent Office and thus attributed to one or several fields of technology. The classification scheme applied is the International Patent Classification (IPC).

A Patent is a written document explaining an invention with exclusive right. It is used to protect an inventor/scientist and to prevent other from making profits without permission. It is also used as an authority paper permitting license holders to duplicate the results. A patent application requires a combination of legal documentation and technical papers. This issue makes patent writing a very different writing style.

In India, patent applications can be filed by a patent agent or an individual having some scientific and technical background to understand the invention. However, no one can understand the invention better than the inventors themselves. Document preparation requires healthy discussions between the inventor and agent. For inventors, a good understanding on patent writing style can greatly facilitate the documentation process. Before filing the patent application inventor must be sure about that the subject is eligible for patent protection, the invention has something new, the invention is not obvious and is not easily predictable from general consensus, and the invention has practical application.

Abstract

Issues regarding intellectual property rights and their protection are heralded nowadays in the scientific arena both in developed and developing countries. IPR is being given greater attention and importance due to the projected idea that it is a dependable means through which greater skills and knowledge can be utilised to serve as a reliable resource for the upliftment of the economy as well as knowledge dissemination. In context of microorganisms, India does not allow patenting of microbes whichalready exists in nature assuch but genetically modified version of the same microorganism with enhanced and improved efficacy can be patented. The deposition of microorganisms in a culture collection recognized as an international depository authority (IDA) is necessary if intellectual property rights regarding these microbes are to be claimed. An action plan for developing countries towards creating IDAs and preserving the natural gene pool has been evolved. It is likely that IDAs will transform into ‘biological resource centres’ and further into‘global common genetic resources’, with an internationally agreed legal basis for benefit sharing. This chapter is an effort to highlight the genesis of patenting and legalities of patenting microorganism in India.

I. INTRODUCTION

In a global, knowledge-based economy, Intellectual Property Rights (IPRs) are a key to the international competitiveness of both nations and firms. International competition in the traded goods increasingly contains a high degree of innovation. IPRs have thus; become a trade issue and a major component of the World Trade Organisation (WTO). Adequate IP protection at an international scale has become essential for appropriating global revenue streams to support investments in developing state of- the- art technology. Although the concept of intellectual property is very old, there appeared the need to harmonize laws to facilitate international trade and free flow of technology. This became very necessary because it was difficult to obtain sufficient protection in the other countries of the world, in view of the disparity in the laws in each country. As per World Intellectual Property Organisation (WIPO) definition, intellectual property refers to creations of the mind, inventions, literary and artistic works, symbols, names, images and designs used in commerce. Broadly, intellectual property is divided into two categories. The first category covers industrial property, which includes patents, industrial designs and trademarks, all of which have industrial applications. The other refers to copyright laws, which are applied to such things as literary, dramatic and artistic works; rights relating to performing artists, the production phonograms and rights of broadcasters in their radio and television programs.¹ Patented inventions have, in fact, pervaded every aspect of human life, from electric lighting and plastic, to ballpoint pens and microprocessors. During a time when the future of many industries seems uncertain, one industry in particular appears to be positioned for expansion and enduring success. This is the biotechnology industry, which according to some analysts will be a major driving force behind the new economy of the 21st century.2 This seemingly lofty prediction is based in large part on the immense promise offered by biotechnology. The innovations developed with biotechnological techniques promise to prolong and improve our lives and the world we live in by achieving advancements in health care, agriculture, food products and production, industrial processes and environmental preservation. Biotechnology is not a new science and it has existed in some form or the other for centuries. Biotechnology in one form or another has been part of human development since the dawn of agriculture. Human ingenuity has led to increased production and greater diversity and quality of livestock and varieties of crops. Today’s food crops and domestic animals embody the benefits of many generations of selection and breeding. However, the advent of genetics has opened exciting opportunities in this sector, because of its numerous applications, which range from improvement of human health and food production to reduction of environmental damage. These opportunities are also coupled with controversies that not only challenge the laws within which society functions, but also our ethical and religious beliefs.

1    Introduction to Patent Laws    540

2.    An Overview of the Patenting Process    541

    2.1.    Inventor’s disclosure, 542
    2.2.    Patentability search, 542
    2.3.    Patent application preparation, 542
    2.4.    Patent application amendment, 542
    2.5.    Patent application examination, 543
    2.6    Main parts of a patent, 543
    2.7.    Granting of patent, 544
    2.8.    Date and term of patent, 544
    2.9.    Provisional specification, 544
    2.10.    Complete specification, 545
    2.11.      Cost of patenting, 545

Chapter I: Preliminary

1. Short title, extent and commencement
 
    (1)    This Act may be called the Patents Act, 1970. 
    (2)    It extends to the whole of India. 
    (3)    It shall come into force on such date as the Central Government may, by notification in the Official Gazette, appoint: 
PROVIDED that different dates may be appointed for different provisions of this Act, and any reference in any such provision to the commencement of this Act shall be construed as a reference to the coming into force of that provision.

Section 3.1 Biotechnology Patents – Scope and Controversies
3.1.1 Introduction
Biotechnology, a field at the intersection of biology and technology, generates innovations that are often groundbreaking and commercially significant. As such, patents have become a vital tool in protecting biotechnological inventions. However, the unique nature of biological materials and living systems presents unprecedented legal, ethical, and commercial challenges, sparking ongoing debates globally. This section delves into the scope of patenting in biotechnology and explores the controversies surrounding such patents.
3.1.2 Scope of Biotechnology Patents
Biotechnology patents cover a wide array of inventions that are novel, non-obvious, and industrially applicable. These may include:
1. Genetic Materials and Constructs
• Isolated DNA/RNA sequences, including genes and promoters
• Synthetic nucleic acids and gene editing tools (e.g., CRISPR-Cas systems)
2. Microbial Inventions
• Genetically modified microorganisms (GMMs) for bioremediation, fermentation, or synthesis of pharmaceuticals

To fully harness the potential of human creativity in industrial applications, it’s essential to safeguard and organize it effectively. One of the best ways to achieve this is by obtaining a patent. The term “patent” is derived from the Latin word “patere,” meaning “to lay open” or make available for public inspection. A patent is an exclusive right granted by the government to an inventor/creator for a limited time in exchange for disclosing their invention for public use. With this right, the patent holder can prevent others from making, using, selling, or exploiting the invention for a certain period, thereby providing commercial benefits to the inventor.

Patents are among the oldest forms of intellectual property rights and are territorial in nature, offering protection only within the country where they are granted. However, through conventions and the Patent Cooperation Treaty (PCT), applicants can seek protection in multiple countries. Obtaining a patent grants the inventor a monopoly right to control the product’s production, sale, and marketing. Although the rights granted through a patent are limited to a specific country, extending protection to all contracting countries is possible through a PCT application.

This chapter provides an insight into the genotypic and phenotypic correlations between plant traits. It incorporates the study of genotypic and phenotypic path analysis and the understanding of genetic variability, all illustrated through practical examples in R, relevant to plant breeding research.

Path Analysis

Path analysis explains not only the direct impact of one character on another but also indirect effects mediated through other variables in the system. The approach is similar to the analysis of variance and is sometimes referred to as the analysis of correlation coefficients. A notable feature of path coefficients is that they are standardized partial regression coefficients, devoid of units. This standardization allows for the direct effects of different variables to be compared and ranked based on their magnitude. This approach was first applied in plant studies by Dewey and Lu in 1959, particularly to examine the factors influencing seed yield.

Path Coefficients

In the computation of path coefficients, a path diagram is translated into a series of simultaneous equations. These equations reveal the direct and indirect contributions of causal variables to the outcome. For example, in the field of plant breeding: consider the yield of forage (Y) being influenced by different variables. These could include the leaf length (X1), leaf width (X2), and number of leaves per plant (X3).

Ornithosis

Ornithosis is caused by Chlamydia and characterized by enlargement of liver and spleen, serofibrinous pericarditis, air sacculitis and enteritis. This is also known as chlamydiosis, psittacosis and is more common in parrots, pigeons and other psittacine birds.

Etiology

• Chlamydia psittaci group B

• Size 0.3 to 1.5 m

• Disease spreads from wild birds

Answer the followings
    Q.1.    What is the different stage of pathogenesis in mastitis?
    Ans.    There are three stages in pathogenesis 
These are as follows:
Invasion: here pathogens move from the exterior of teat to milk inside the teat canal.
Infection: Here pathogens multiply rapidly and invade the mammary gland.
Inflammation: In this stage clinical mastitis occurs with varying degree of clinical abnormalities of milk and udder.
    Q.2.    Of these phases, which phase is important to reduce the incidence of mastitis in control program?
    Ans.    Invasive stage is very important. The incidence of mastitis can be reduced by taking preventive measures at invasive stage by good management and good hygiene practices.
    Q.3.    What are the common abnormalities encountered in udder during mastitis?

Pathogenesis: Role of enzymes

The chain of metabolic events that bring about the disease is pathogenesis. It involves the virulence of the pathogen, susceptibility of the plant and impact of the environment. It is called disease triangle. Penetration infection, invasion, colonization and reproduction are the events that occur during pathogenesis, and lead to development of disease.

The establishment of pathogen in the host and consequent development of disease involves a chemical interaction between the host and the pathogen. The pathogen employs offensive chemical weapons to break host barriers, which the host resists with all its might. Parasitism and disease resistance run parallel and are inseparable, A biochemical ‘tug of war’ ensures between the host and the pathogen, in which one tries to outwit the other. Enzyme, toxins and growth regulators are the important chemical weapons of the pathogen. Viruses, however, because of their basic nature, do not produce any of these chemicals.

Pathogens produce these substances either in normal course of their activities (constitutively) or when, they grow on certain substrates such as their host plants (Inducible). Plant pathogenic enzymes disintegrate the structural components of host cells, breakdown inert food materials in the cell, or affect components of the protoplast directly and interfare with its functioning system. Toxins seem to act directly on protoplast component and interfare with the permeability of its membrane and with its function. Growth regulators exert a hormonal effect on the cells and either increase or decrease their ability to divide and enlarge. Polysaccharides seem to play a role only in the vascular diseases, in which they passively interfere with the translocation of water in the plants or they may also be toxic.

Pathogens are different from parasites, Parasites penetrate into the host and obtain nutrients from the host. They live inside the host without causing any other damage. They may be at times symbionts also i.e. they may be beneficial to the host. The examples for parasites are Rhizobium spp. which form nodules in leguminous plants and mycorrhizal fungi. Pathogens not only take nutrients from the host but also damage the host severely. They induce numerous symptoms of the disease and even kill the plants.

Pathogens in their life cycle enter into two distinct phases. One is biotrophic and the other is necrotrophic phage. In the biotrophic phase they invade the host cells inter and intracellularly and establish themselves in the living cells. In the second phase, they kill the cells and obtain nutrition from the dying cells. This phase is called necrotrophic phase. In case of obligate pathogens the biotrophic phase may be much longer while in case of facultative saprophytes, long biotrophic phase may be followed by necrotrophic phase. In case of facultative parasites necrotrophic phase will be much longer with short biotrophic phase. However in case of all pathogens, both the phases may exist either as a short or long spell.

In the biotrophic phase the pathogens establish themselves in the host cells. The first barrier between host plant and the attacking pathogen is the cuticle. Host cells have cell wall, structure surrounding the protoplast. Cell wall is divided into three regions: middle lamella, primary wall and secondary wall. Below the cell wall membranes are found. The membrane provides a semi permeable barrier between the cell and its external environment. The membrane consists of lipids and proteins. During the biotrophic phase, the pathogen invade the cells by degrading cuticle, middle lamella,cell walls and cell membranes, by producing a series of enzymes.After the biotrophic phase, the pathogens produce toxins which kill the cell and enter into the necrotrophic phase. Thus, enzymes, toxins, growth regulators are important tools of the pathogens for their pathogenesis.

Definition

Pathogenesis can be defined as the chain of events leading to the development of a disease. In another words it is also called disease cycle.

It tells us about

Calcification

• Calcification is abnormal deposition of calcium salts in tissue other than bone.

• Calcium is normally present in blood and deposited in bones.

• Calcium if deposited in an abnormal tissue with normal or abnormal blood calcium level is considered as pathological condition.

Pathological calcifications are

1. Metatstatic calcification

2. Dystrophic calcification

Diseases are among the greatest deterrents to the sustained production in aquaculture. White spot disease (WSD) in penaed shrimp and epizootic ulcerative syndrome (EUS) in fresh and brackish water fishes are the well known devastating diseases with serious impact in aquaculture. Aquaculture medicine which broadly encompasses prevention and management of diseases in cultured aquatic organisms becomes a vital requirement for a sustained industry.

The four K’s essential for scientific aquaculture health management are knowledge about the disease process, knowledge about the pathogen, knowledge about the host and the knowledge about the environment. Disease development process is often complicated and involves host-pathogen- environment interactions. Knowledge about the pathogen, attaching and entering the host, deriving nourishment, reproduction, transmission, overcoming host defence barriers, etc are very essential. Susceptibility of a host to a pathogen is important which depends on host species, age, size, immuno competence and stress response. Besides knowledge about how the temporal and spatial aspects of environment stress the host and favour the pathogen to cause disease is vital

Disease Development Process

There exist a delicate balance between the host, pathogen and the environment. When this delicate balance gets upset, disease can result. Aquaculture environments can stress the host, favour the pathogen and result in disease development. To appreciate the process of disease development understanding the pathogenicity mechanisms of the pathogens, disease resistance mechanism of the host and the role of the environment is essential. Furthermore, role of various pathogens, their adaptive modifications, the functional importance of the target tissue, interaction between pathogen and host at the target tissue level, pathogenicity mechanisms of pathogens, etc are necessary to gain insight into process of disease development. Only when a pathogen can establish on or in the host, proliferate, overcome the non-specific and/or specific defense barriers of the host, produce the pathogenic factors, cause cellular and tissue damage, produce significant pathological changes, impair the function of the target tissue cause clinical disease often with mortality. This process is very complicated which often get accelerated by stress and environmental factors. However, the sequence of disease development will to a large extent depend on the nature and load of the pathogen (parasite, bacteria, fungi, virus), its intensity per unit area or unit weight of the host, size of the host and environmental factors.

Tuberculosis

Tuberculosis is a chronic bacterial disease of cattle, buffaloes, sheep, goat and pigs caused by Mycobacterium sp. and characterized by presence of tubercle nodules in lungs, spleen and lymph nodes (Fig.2.1).

Etiology

• Mycobacterium tuberculosis

• M. bovis

Pathogenesis

Disease spreads through contact with infected animals or their discharges or morbid tissues. The infected animals release the organisms through sputum at coughing and contact animals get infection through droplet inhalation.Besides sputum, faeces, urine, vaginal discharges, semen, milk, lymph and wound discharges may act source of infection. It is also transmitted through contaminated instruments, utensils and beddings. After entry through inhalation or ingestion, bacilli localizes at the point of entry and produce typical tubercle in associated lymph nodes. Mostly pharyngeal and mesenteric lymph nodes are affected. From lymph nodes, infection may extend across body cavities, blood vessels and lymph vessels. The inhaled organism enter in the bronchial tree after lodging in bronchi a tissue reaction takes place. Neutrophilic infiltration is there and when neutrophils are necrosed, macrophages come to destroy the organism but they fail then many macrophages becomes elongated to form epithelioid cells, the hall mark of granulomatous inflammation. Some macrophages are joint together to form giant cells to destroy the acid fast bacilli. As a consequence of this some bacilli are phagocytosed and are destroyed. A zone of lymphocytes, macrophages, epithelioid cells, giant cells and fibrous connective tissues are formed around the central necrosed area.

Salmonellosis

Salmonellosis is caused by G-bacteria Salmonella and characterized by early chick mortality with necrosis and hemorrhage in liver, heart and spleen and enlarged bronze coloured liver with focal or diffuse necrosis, marbled spleen and/or oophoritis and salpingitis in adults (Fig.4.1).

Etiology

• Salmonella enteritidis var. Galinarum (S. Galinarum).

• G-, rod, non lactose fermenter.

• White small colonies on MLA and pink on BGA.

Developmental Anomalies

Persistent right aortic arch

This is a developmental anomaly of aorta in which the aorta develops from right arch present on right side of trachea and oesophagus. The ductus arteriosus forms a ring around trachea and oesophagus by connecting aorta and pulmonary artery. This ring causes partial obstruction of trachea and/or oesophagus.

Patent ductus arteriosus

The ductus arteriosus is a short blood vessel which connects pulmonary artery to aorta in foetal life for diversion of blood. Normally, soon after birth this duct is sealed and remains in the form of a ligamentum arteriosum. But sometimes this ductus arteriosus remains open and blood is continuously shunted between aorta and pulmonary artery, after leading to congestive heart failure, pulmonary hypertension and cyanosis due to mixing of venous and arterial blood (Fig. 3.1).

Chlamydiosis

Chlamydiosis is an infectious disease of animals caused by Chlamydia sp. and characterized by encephalitis, polyarthritis and pneumonia in calves and abortions in cows and sheep.

Etiology

• Chlamydia psittacii

Pathogenesis

Chlamydial infection spreads through inhalation of contaminated dust from infected birds. Organism multiplies in lungs and through blood it spreads to liver, spleen, kidneys, brain, joints and placenta to cause pathology.

Characteristic symptoms

Calves

• Fever, dyspnoea

• Nasal discharge, hypersalivation

• Swelling of joints

Developmental Anomalies

Congenital icthyosis

Congenital icthyosis is scaly epidermis which resembles the skin of fish and occurs due to a simple autosomal recessive homozygous gene in calves. This condition is characterized by scaly, horny, thick epidermis divided into plates by deep fissures. Microscopically, there is thick keratin layer over the epidermis (Fig.1.1).

Epitheliogenesis imperfecta

Epitheliogenesis imperfecta is a congenital defect characterized by discontinuity of epithelium on skin leaving patches without squamous epithelium mostly at feet, claws and oral mucosa. Such defect may occur in calves which succumb to infection after birth or such foetus may abort. This disease condition is inherited as an autosomal recessive trait.

Developmental Anomalies

Epitheliogenesis imperfecta of tongue

Abnormal smooth surface of tongue due to small filiform papillae. It occurs as a defect in autosomal recessive gene and occurs in Holstein-Friesian cattle. This is also known as smooth tongue.

Cleft palate

This is most common congenital abnormality that occurs due to failure of oral nasal cavity to divide leaving cleft. It may also extend towards lips producing ‘harelip’ condition.

Mega colon

There is distention of colon which abruptly terminates in rectum due to mutant gene in dogs.

Pathology of Endocrine System

Pathology of Hypothalamus

The lesions in hypothalamus may cause diabetes insipidus characterized by polydipsia and polyuria with low specific gravity of urine. It occurs due to deficiency of antidiuretic hormone vasopressin.

Etiology/ Occurrence

• Lesions in hypothalamus and/or pituitary.

• Adenoma and adenocarcinoma of pituitary.

• Necrosis of hypothalamic nuclei due to larval migration.

Ringworm

Ringworm is a fungal disease of skin affecting animals characterized by popular skin lesions in circular form discharging serus exudate.

Etiology

• Microsporum canis- dogs

• M. gypseum- dogs, horse, pig

• Trichophyton verrucosum- bovines

• T. equinum- horses

Pathogenesis

The fungi enter in skin through abrasion and the hyphae appear in stratum corneum after germination and invade the hair follicles. The hyphae growth and spore formation in stratum corneum leads to hyperkeratosis and the fungus spreads centrifugally from the point of primary invasion leading to ring shaped lesion (Fig.8.1).

Aspergillosis

Aspergillosis is a fungal disease of poultry caused by different species of Aspergillus sp and characterized by granulomatous nodules in lungs, thickening of air sacs and presence of fungal growth in lungs and air sacs in early age of chicks. It is also known as Brooders pneumonia (Fig.8.1).

Etiology

• Aspergillus fumigatus

• A. flavus

• A. nidulans

• A. glaucus

• A. niger

• A. candidus

Female Genital System

Developmental Anomalies

Agenesis

Absence of ovary, uterus, oviduct and cervix in females. It may be unilateral or bilateral.

Hypoplasia

Complete or partial lack of germ cells in ovaries. Hypoplasia of uterus is related with agenesis of gonads. Ovaries of freemartin are also hypoplastic. Hermaphrodite animal has ovary and testicular tissue both in the gonads.

Hermaphroditism

In hermaphrodites, there is presence of organs of both sexes in same individual animal. Both ovarian and testicular tissue occur in one animal leads to sterility in animal (true hermaphrodite) while in pseudohermaphrodite the gonadal tissue of only one sex is present but there is some degree of development of opposite sex organs.

Developmental Anomalies

Hereditary anemia

Hereditary anemia has been reported in mice due to defects in erythropoiesis or reduced vitality of erythrocytes. Erythropenia along with leucopenia occurs in mouse foetus on 20th day of gestation due to defective autosomal chromosome 4. Sex linked anemia in mouse is hypochromic with deficient bone marrow and occurs in hemizygus males or homozygus females. This anemia occurs due to deficiency of iron as a result of poor absorption from gastrointestinal tract.

Autoimmune hemolytic anemia in foals

It occurs due to incompatible blood group antigens of male and female parents. The mare does not have that blood group antigen but foetus acquires it from father. The foetal blood exposed to dam through placental exchanges leads to induction of antibody production in mares against foetal blood group antigen. These antibodies accumulate in colustrum and when foal suck the milk from mares, they are readily absorbed through G.I. tract of foals in blood and cause destruction of erythrocytes leading to anemia.

Tyzzer’s disease

Tyzzer’s disease is an acute infectious disease of laboratory animals including rats caused by Clostridium spp and Characterized by watery diarrhoea, necrotic hepatitis and death

Etiology

• Clostridium piliforme

• Gram positive, Spore forming, Anaerobe

Pathogenesis

• Horizontal transmission- faecal oral route

• Contaminated feed, water

• Bacteria in gut causing enteritis

Pathology of Muscles

Equine Rhabdomyolysis

It is also known as Azoturia or Monday Morning Disease. The disease occurs in well fed horse after a spell of inactivity. Suddenly after walking a few steps, the horse is unable to move further and feels pain with intense sweating and hardening of muscles.

Etiology

• Accumulation of lactic acid in muscles.

• High glycogen storage.

• Lack of oxygen supply.

Macroscopic features

• Hardening of muscle just like wood.

• Urine is dark brown with myoglobin – myoglobinuria.

• Tonic spasms in muscles.

• Atrophy of affected muscles in chronic cases.

Contagious

Bovine Pleuropneumonia (CBPP) Contagious bovine pleuropneumonia (CBPP) is an infectious disease of cattle caused by Mycoplasma sp. and characterized by cuprous pneumonia, pleurisy and dilation of lymph vessels (Fig.5.1).

Etiology

• Mycoplasma mycoides

Pathogenesis

The infection spreads through inhalation of droplets from infected animals. The recovered animals act as source of infection at least for a period of 3 years. After entering through respiratory tract the organism reaches to bronchioles. It may remain in retropharyngeal gland from where it may spread in whole body. The organism from bronchioles enter into interlobular septa and causes inflammation followed by edema which causes dilation and subsequent thrombosis of lymph and blood vessels prior to development of pneumonic lesions. Death occurs due to anoxia and toxaemia.

Chronic Respiratory Disease (CRD)

Chronic respiratory disease is caused by Mycoplasma gallisepticum and E.coli in birds under poor management and characterized by cloudy air sacs with thickening of their wall, accumulation of cheesy material in air sacs and lungs (Fig.6.1).

Etiology

• Mycoplasma gallisepticum

• E.coli

• Bad management like poor ventilation and inclement weather conditions

• Disease occurs more during winter and rainy season.

Nervous system is composed of brain, spinal cord, and peripheral nerves. The neuron is a basic functional unit of nervous system. Necrosis of neurons in brain is known as encephalomalacia while necrosis of neurons in spinal cord is termed as myelomalacia. If the necrosis occurs in grey matter it is known as polioencephalomalacia while necrosis of neurons in white matter is called as leukoencephalomalacia. There are three types of scavenger cells in nervous system known as microglial, oligodendroglial and astrocytes. Microglial cells surround the necrotic neurons and are known as satellite cells and the process is called as satellitosis. As the neuron dies, it is engulfed by microglial cell and this process is termed as neuronophagia. The necrosis of nerve fibers starts from myelin sheath and this change is called demyelination or Wallerian degeneration.

Nervous system is composed of brain, spinal cord, and peripheral nerves. The neuron is a basic functional unit of nervous system. Necrosis of neurons in brain is known as encephalomalacia while necrosis of neurons in spinal cord is termed as myelomalacia. If the necrosis occurs in grey matter it is known as polioencephalomalacia while necrosis of neurons in white matter is called as leukoencephalomalacia. There are three types of scavenger cells in nervous system known as microglial, oligodendroglial and astrocytes. Microglial cells surround the necrotic neurons and are known as satellite cells and the process is called as satellitosis. As the neuron dies, it is engulfed by microglial cell and this process is termed as neuronophagia. The necrosis of nerve fibers starts from myelin sheath and this change is called demyelination or Wallerian degeneration.

Equine Rhabdomyolysis

It is also known as Azoturia or Monday Morning Disease. The disease occurs in well fed horse after a spell of inactivity. Suddenly after walking a few steps, the horse is unable to move further and feels pain with intense sweating and hardening of muscles.

Etiology

• Accumulation of lactic acid in muscles.

• High glycogen storage.

• Lack of oxygen supply.

Pathology of nutritional deficiency diseases are described in chapter etiology of this book. However, specific deficiency of nutrition that leads to development of clinical signs and lesions in poultry are summarized as under (Fig.2.1 & Fig.2.2):

Vitamin Deficiency

1. Hypovitaminosis A

• Vitamin A is considered infection resisting vitamin because it facilitates the proper development of bursa, immunity and epithelium on mucosal and skin surfaces.

• Deficiency of vitamin A leads to swollen glands in oesophagus i.e. nutritional roup.

Trypanosomosis

Trypanosomosis is an infectious disease of animals caused by protozoan parasite and characterized by emaciation, enlargement of spleen and lymph nodes, petechiae on serous membranes, ulceration on tongue and gastric mucosa and gelatinous exudate in subcutaneous region.

Etiology

• Trypanosoma evansi

Pathogenesis

The disease is mainly transmitted through bite of flies like Tabanus, Stomoxys, Haematopota etc. The carrier animals remain as potential source of infection. The pathogenesis of disease is not completely known. After entering in mammalian host, trypanosomes multiply in blood stream by binary fission leading to parasitaenia. The parasites has variable surface glycoproteins which cause continuous exposure of immune system leading to hyperplasia of spleen and lymph nodes. In chronic cases, due to formation of antigen- antibody complexes glomerulonephritis and vasculitis is seen.

Roundworms (Nematodes)

1. Ascaridia galli

A. galli is the common roundworm of poultry seen in intestines at the time of necropsy. This parasite may cause retardation of growth, loss of egg production, catarrhal enteritis and sometimes mortality due to obstruction of gut (Fig.9.1).

Etiology

• A. galli parasites are grey, thread like 5-10 cm in length.

• Eggs are elliptical with thick and shiny wall.

Pathogenesis

Transmission occurs through faecal - oral route. The eggs may survive for several months in litter and they take at least 10-15 days to develop the infective stage. The eggs of parasites hatch in proventriculus or intestine to develop fully grown parasite within 40-50 days.

Spongiform encephalopathy

Spongiform encephalopathy is an infectious disease of animals caused by prion proteins and characterized by presence of vacuoles in brain.

Etiology

• Prion proteins

• Sheep – Scrapie or Ovine spongiform encephalopathy

• Cattle - Bovine spongiform encephalopathy (Mad cow disease)

• Feline encephalopathy

Pathogenesis

Scrapie is also known as ovine spongiform encephalopathy. The principle means of transmission of disease is from infected mother to their lambs early in life; placental transmission has also been reported. The incubation period of disease is very long (2-5 year). The clinical form is restricted in adults. The prion proteins (PrP) occur normally in the central nervous system of all domestic animals and man bounded with neuronal surface. Animal susceptible to prion disease have a gene (PrP gene) which encodes for normal “Prion protein (PrP)” or “cellular prion protein (PrPc). In scrapie prion protein (PrPsc)/ scrapie associated fibril protein (SAI) is generated which are resistant for protease digestion. Accumulation of PrPsc in neural tissues appears to be the cause of the pathology in prion disease. When prion protein contaminated meat and bone meal are fed to the cattle as part of their concentration, the agent (prion) got introduced into cattle. Prion protein (PrP) on reaching brain slowly and progressively converted into and abnormal form (PrP sc) and this abnormal protein causes development of lesions including vacuolation in nerve cells.