eChapters

Spikeborer : Helicoverpa armigera : Noctuidae

Larvae of this polyphagous moth feed on the spikelets, flowers and developing seeds. The young larvae bite holes into the spikelets and the grown up ones attack the mature spikes

Diamond back moth: Plutella xylostella: Plutellidae
 
The adults of this moth are small, greyish brown having pale whitish narrow wings and with inner margins yellow. There are three pale whitish triangular markings on hind margins of each forewing. At rest, when both forewings come together, they form a dorsal median patch of three diamond shaped yellowish white spots that give them their name diamond back moth. Hind wings have a fringe of long hairs.

Crust is characterized by the presence of desquamated squamous epithelial cells. The dried exudate consists of necrotic cell debris, leucocytes, RBC’s, plasma proteins and microorganisms. It is classified into serous crust (eosinophilic protein exudates), hemorrhagic crust (RBC’s), cellular crust (degenerative leucocytes mainly neutrophils), serocellular crust (mixture of serum or plasma or leucocytes) and palisadic crust (presence of leucocytic infiltration, pustules and parakeratosis organized in a horizontal manner).

Etiology

Cryptococcosis (KRIP-toe-cock-co-sis) is caused by the fungus, Cryptococcus neoformans (KRIP-toe-cock-kus knee-O-for-mans). It is found worldwide and primarily affects cats and people with weak immune systems.

Cryptosporidiosis is a protozoan disease.

Species

1. C. meleagridis: Infects small intestine.
2. C. baileyi: Infects digestive tract (bursa of Fabricius and cloaca), kidneys and respiratory tract.

Fruit flies: Bactrocera cucurbitae:Tephritidae

This pest is more serious in bitter gourd, snake gourd and to a certain extent on ridge gourd. Other cucurbits are attacked to a lesser level. Damage by this pest causes losing the fruit quality, rotting and fruit drop. The adults lay many eggs inside the fruit sing their big ovipositor that hatch out into worm like apodous maggots. Feeding by the maggots on the pulp of fruits result in rotting, yellowing and fruit drop. The dropped fruits allow pupation by the maggots in the soil from where they emerge out as adults and start egg laying on fresh frits.

Introduction 
The discovery and introduction of antimicrobial agents to clinical medicine was one of the greatest medical triumphs of the 20th century that revolutionized the treatment of bacterial infections. However, the gradual emergence of populations of antimicrobial resistant pathogenic bacteria, resulting from use, misuse and abuse of antimicrobials has today become a major global health concern. Antibacterial drugs have revolutionized our ability to control bacterial disease, and their clinical availability has led to dramatic decreases in morbidity and mortality. (Walsh and Wright, 2005). As such, these therapeutics underpin modern medicine. Despite the integral role of antibiotics in sustaining our modern lifestyle, they are undervalued in both cost and significance by society. Over the past century, their use has provided strong selective pressure on microorganisms, leading to preferential survival and spread of those harbouring antibiotic resistance mechanisms. Multidrug resistance is now commonplace amongst bacterial pathogens with antibiotic resistance now affecting all antibiotic classes. (Coates et al, 2011). This is particularly worrisome in the case of Gram-negative bacteria (e.g. Pseudomonas aeruginosa and Acinetobacter baumannii) for which treatment options are already limited. The ‘broken’ economics of antibacterial research and development is often quoted as the main reason for the lack of new therapies but the truth is that it is hard to discover new antibacterial drugs, and the science is not sufficiently advanced to allow discovery of efficient and effective drugs. This has led to fears of a ‘post-antibiotic era’ as it has been estimated that 5–20 novel antibacterial drugs need to enter clinical development in order to effectively contend with the current resistance problem. However, given the attrition rate within the existing drug discovery model, at least 200 discovery programmes would be needed in order to achieve this outcome. Hence, new approaches to antibiotic discovery are needed. The antibiotic pipeline The antibiotic pipeline is not what it once was.4 Pharmaceutical companies were once the main provider of novel antibiotic molecules but they largely withdrew in the late 1990s because of the lack of success and low financial returns in bringing new antibacterial drugs to the market.5 The environment of discovering and developing new antibiotics was quite different during the so-called ‘golden era’ of drug discovery. Antibiotics worked remarkably well because resistance was low and physicians had access to a variety of efficacious antibiotics. Antibiotic research and development programmes were inclined to focus on improved pharmacology to achieve less frequent dosing e.g. once a day, rather than innovative new antibiotics. Natural product screening strategies tended to result in rediscovery of compounds rather than finding new ones. There was also no need to consider those natural products with undesirable properties such as toxicity. Today, only a few large companies such as GlaxoSmithKline, Novartis, Merck and Roche are still actively engaged in antibiotic R&D, with many of the original antibiotic provide.The natural world remains the largest source of novel drug scaffolds making this a viable option in the search for new antibiotic compounds. Advances in bacterial culture techniques, molecular biology and metagenomics will make natural product drug discovery easier and more costeffective, obviating these limiting factors. Screening procedures must include whole-bacterial cell assays, addressing the issue of bacterial permeability and efflux early in the discovery process (Shore and Coukell, 2016). Additionally, the generation of training schemes by, and with, pharmaceutical companies that cover all aspects of the pipeline and include natural product drug discovery, are essential and will ensure that expertise is passed on to future researchers. Investment should also be made into the study of previously characterized lead compounds that did not reach the clinic, so called old leads. The reasons that led to these compounds being dropped from further development vary, ranging from financial issues to trial design, dosing problems and toxicity. It may be that there is now sufficiently improved technology and expertise to develop these as safe and efficacious antibacterials. The revival of interest in old leads could also provide an additional source of novel antimicrobials. A freely accessible database of antibiotics that were never developed has recently been launched, Antibiotic with the aim to reduce unnecessary duplication of Pharmaceutical agents such as nanospheres, liposomes, and immunoglobulins for example have been developed which can alter the pharmacodynamics of a compound, act as carriers for sustained or controlled drug release, and for immunization therapy.

Haemoprotozoan parasites are responsible for causing severe infections in humans as well as animals across the world. The important hemoprotozoan diseases of livestock are trypanosomosis, theileriosis, babesiosis, and
anaplasmosis, which are caused by several species of Trypanosoma, Theileria, Babesia, and Anaplasma, respectively, in several species of livestock. These diseases caused huge impact on health and productivity of livestock as well as human beings and causes great economic losses to the livestock production n terms of morbidity and mortality worldwide. In India, the annual economic loss has been esteemed in the livestock due to theileriosis, babesiosis and trypanosomosis of Rs 8426 crore, Rs 4000 crore and Rs 4474 core, respectively. The major clinical signs of the haemoprotozoan disease varies from fever, anorexia, anaemia, abortion, and even death in the acute form of infections. The symptomatological treatment is a quite common practice in the field condition to treat the animals suspected with haemoprotozon infection leading to the development of resistance in animals to currently available drugs against haemoprotozoans. The accurate and prompt diagnosis of haemoprotozoan infection is a key to control these diseases. Routine diagnosis of haemoprotozoan infection has been rely on clinical findings and microscopical demonstration of the infective parasitic stages in the blood or tissue fluid smear. Conventional diagnostic techniques such as Microscopical examination techniques and Immunological assay provide the definite clues about parasitic infections in general, but these tests have some limitations.

Mealy bugs: Ferrisia virgata, Planococcous lilacinus, P. pacificus, Maconellicoccus hirsutus, Perisopneumon ferox: Pseudococcidae

The fruit is seen covered with a mealy coating due to colonies of small reddish-white mealy bugs. They also infest leaves, shoots and buds. Due to sucking of sap by nymphs and adult female mealy bugs, fruits remain small in size and become shrivelled. Large number of mealy bugs is seen in the tip of the petiole abd also on the grooves of fruits epicarp. The fruit also becomes blackish due to the development of sooty mould.

Cutaneous lymphoma has two types viz. Epitheliotropic and non- epitheliotropic. Epitheliotropic lymphoma (mycosis fungoides) is mostly seen in the skin which is characterized by erythema, pruritus, alopecia, scaling, erosion and ulceration. It mostly occurs in plaques or nodules (Figure 80). Non-epitheliotropic lymphomas are observed as nodules. They are usually sheets of nodules seen in the deep dermal and subcutaneous tissue.

The mast cell tumors are focal or multicentric in nature in the skin and occasionally in the internal organs. It is more common in middle aged dogs without sex predilection.

It is more common in old dogs and also mostly observed in the cutaneous region of trunk and legs.

Grossly, the tumour appears as solitary to multiple masses as white, pink to red, smooth, and raised nodules. Alopecia and ulceration are also observed. It is mostly observed in the pinna and digits.

Cystic ovarian disease (Cystic ovarian degenertaion or ovarian cysts) is a common ovarian dysfunction in cattle and causes huge economic loss to farmers due to its high incidence and negative impact on the reproductive performance of cow. Animals having cysts on ovary result in anoestrum as the most significant clinical sign. Althouugh the exact cause that leads to cystic ovarian disease is not yet fully clear but altered release of LH hormone is the most accepted hypothesis.

Cytauxzoonosis is an emerging tick-borne disease of domestic cats and wild felids caused by the protozoa of the genus Cytauxzoon. The common clinical findings in affected cats are similar to other hemoparasitic infections namely anorexia, depression, anemia, vomiting, icterus, and high fever. The first reporting of feline cytauxzoonosis with four fatal cases was done by Wagner in Missouri, USA in the year 1976.

Bobcats (Lynx rufus) are recognized as the natural wild reservoir of Cytauxzoon felis with prevalence reaching up to 100% in some enzootic areas (Zieman et al., 2017). This infection is highly fatal in domestic cats with 97% mortality without treatment (Meinkoth and Kocan, 2005). However, subclinical infection in some cats has also been evidenced i.e., they were infected with C? felis but did not display the acute clinical signs of the disease before diagnosis (Brown et al., 2010 and Rizzi et al., 2015).

Several other wild felids apart from bobcats and domestic cats have been found to be affected by fatal or nonfatal Cytauxzoon sp. infection. These include lions, jaguar, cougars, pumas, ocelots, Iberian lynx, meerkats, European wild cats and Asiatic wild cat, panthers, and tigers (Jakob and Wesemeier, 1996; Rotstein et al., 1999; Yabsley et al., 2006; Andre et al., 2009; Filoni et al., 2012 and Furtado et al., 2017).

Adrenal Tumours

• Adrenal cortical adenoma had normal secretory cells
• Most cells had naked nuclei in the abundant cytoplasm
• Basophilic cytoplasm with abundant clear lipid vacuoles
• Round uniform nuclei

Discrete Cell Tumours

(Round / discrete / distinctive / unique cell tumours)

General Features

• Exfoliate many cells
• Cells often quite small to medium sized
• Discrete cells
• Do not stick together
• If the smear is very cellular, cells are packed close together in sheets
• However, these cells are not adherent to one another
• There are sharp, crisp cytoplasmic margins between cells

Non-Neoplastic Conditions

Haematoma

Collection of blood in outside of the blood vessels It is more common in external ear

• Presence of erythrocytes, blood filled leococytes (non-degenerative neutrophils and macrophages) and platelets
  • Haemosiderin or haematoidin crystals will be seen

Epidermoid cyst/Epidermal cyst/Epidermal inclusion cysts/Follicular cyst

Cytologically cannot distinguish epidermoid cyst from dermoid cyst

• Constitutes ????V3 to V2 of non-neoplastic/non-inflammatory lesion
• Smear is thick
• Keratin bars, squames and other keratinocytes

Hepatocellular Carcinoma

• The presence of normal appearing hepatocytes of atypical hepatocytes with malignant characters
• Single to clusters of polyhedral or polygonal shaped or pleomorphic cells
• Large round, spherical or oval nuclei
• Higher nuclear cytoplasmic ratio
• Large nucleoli
• Dark blue cytoplasm

Points to Ponder

Collect cytological samples (FNAB) only from enlarged lymph nodes

Do not make attempt to collect samples from normal lymph nodes unless to study normal picture (Academic interest).

Care to be taken to hold the lymph node while collecting FNAB

Otherwise needle may go into perinodal fat yielding fat tissue so also in obesity

Submandibular salivary gland enlargement mimic submandibular lymph node enlargement

Salivary tissue will show epithelial cells, acinar formation and no lymphocytes

Cytological diagnosis of lymphadenopathies can be comfortably and confidently made.

Peripheral Lymph Nodes

Mesenchymal Tumours

General Features

• Do not exfoliate many cells - hypocellular; Low cellularity
• Embedded in extracellular matrix-osteoid, chondroid or collagen
• Single, discrete cells and a few are also seen in dense clumps i.e. Individual or unorganized cluster of spindle cells
• Cells-Elongated, fusiform/spindle shaped
• Cytoplasmic extensions/tails seen on both ends of nucleus; borders ill-defined
• Nucleus elongated/fusiform to oval
• As the malignancy potential increases cells become plumpy with a larger, rounder nucleus and shorter cytoplasmic tails
• Nuclei may be fusiform or oval.
• These tumors cannot be differentiated cytologically.
• Tentative diagnosis made.
• Well-differentiated malignant mesenchymal tumors may resemble actively proliferating granulation and requires histologic confirmation.