eChapters

Introduction

Although the causative agent for the condition has not been identified, experimental studies indicate the association of parvovirus and or Astrovirus. Under experimental conditions, the virus induces clinical signs onlyin fast growing broiler chickens. The clinical signs, based on experimental inoculation of chickens, consist of watery or mucoid mustard yellow colour diarrhoea within 3-5 days after infection. Chickens become stunted, and a variable number of such chickens die during 10 and 20 days. Pronounced weight loss is in around four week’s age. The mortality is low (5 - 10%) however, the morbidity is very high (50 - 80%).

Cage layer fatigue is a term used to describe leg weakness and acute deaths in chickens in cages, and is caused by inadequate calcium, phosphorus and Vitamin D levels in the blood stream. Calcium is required for muscle function, bone formation, and egg shell formation. This condition may be seen even in floor birds under certain conditions. It is seen most often in young hens early in production.

Pododermatitis or bumble foot has many causes including excess weight bearing from obesity or unequal weight bearing between the two feet as a result of lameness of one foot, causing less weight to be placed on that foot and more on the contralateral foot, or from abnormal abrasions of the plantar surface from inappropriate substrate (too sharp or rough, wire, etc.), decreased blood supply to the foot (sometimes from lack of exercise), trauma, or standing for prolonged periods of time, especially in ducks that are not provided with adequate swimming opportunities.

Bumble foot is commonly seen in waterfowl under one or more of the following conditions; obesity, hard substrate, lack of access to water to swim in, malnutrition and underlying disease.

This is localized infection of the feet. It is seen as bulbous swelling of the footpad and surrounding tissues. It appears usually after an injury to the foot pad and causes lameness in one or both feet. Pododermatitis is divided into varying grades depending on the literature source used, but generally includes mild, moderate, and severe grades with the severe grades including osteomyelitis. Infection by various bacteria commonly occurs and superficial wounds may not be present. Sometimes ulcers are formed on the planter surface of the foot. The layers become lame and production lowers, sometimes completely stops. On opening the swelling a foul smelling thick pus is found. The condition is more common in heavy breeds. Early surgery and antibiotic therapy may control the condition. Removal of high roosts reduces the incidence.

CALCIUM & PHOSPHORUS

Source of mineral

Soluble grits (Limestone grits containing chiefly CaCo3) which is soluble in acid medium of crop. It differs from insoluble grits (gravel, granites, sand etc.) which acts only mechanically in the gizzard.

Vitamin A

Source of Vitamin

Berseem, legumes, alfalfa or other grass meal, fish oils, yellow corn, palm oil, commercial Vitamin A concentrate

LICE

Introduction

Lice are common ectoparasites of birds. There are many species of bird lice and are found on chicken, turkey, guinea fowl, duck, goose and pigeon. Lice species prefer a different part of the body. Most of them are straw colour and measure 1-10 mm. Lice from one host can parasitise another host if they are in close contact. For example, a louse from chicken can parasitise guinea fowls kept on the same premises. Hence, the species of lice is determined if cross contamination from another species is suspected. Lice are not highly pathogenic to mature birds. However, severe lousiness may lead to weight loss, as well as low production and death.

HAEMOPROTEUS

Host

Infection with Haemoproteus species is host specific.

H. meleagridis – domestic poultry and pet birds

H. olumbae in pigeons

H. nettionis in waterfowl.

Introduction

1. Various genera of tapeworms are found in poultry. They are:
   1. Raillietina spp.
   2. Choanotaenia spp.
   3. Davainea spp.
   4. Amebotaenia spp. and
   5. Hymenolepis spp.
2. Tapeworms mainly parasitise the small intestine. Tape worms deprive the bird of its nutrition and cause weight loss and decreased egg production.
3. Out of 3 species of Raillitina, Raillietina echinobothrida is one of the pathogenic species as it produces granuloma at its attachment site (nodular disease).
4. They all require intermediate host for their development.
5. Intermediate hosts are common houseflies, ants, beetles and grasshoppers, which makes control of tapeworms difficult.

Introduction

A. Common species of nematodes encountered in poultry are:

1. Syngamous trachea (in the respiratory tract) large 2.00cm size live in the trachea and larger bronchi. Many species of domestic and wild birds are affected. Dyspnea, gasping and head shaking are main clinical signs. Treatment is difficult.
2. Ascaridia galli (in the intestine) They parasitize chicken, turkey, pigeon, quail and guineas. In younger birds parasites cause enteritis. In heavily infected birds clinical signs are emaciation and diarrhea.

Introduction

Chickens are considered one of the most important hosts in the epidemiology of Toxoplasma gondii infection because they are an efficient source of infection for cats that excrete the environmentally resistant oocysts and because humans may become infected with this parasite after eating undercooked infected chicken meat.

Poultry meat is an important part of cuisine, consumed widely all over the world; therefore, consumption of uncooked or not properly cooked poultry meat may pose a risk factor for T. gondii infection in humans or animals.

Etiological Agent

Trichomonas gallinae, a flagellate protozoan. Strains vary in pathogenicity. The disease continues to be of significance in pigeons and doves. It has also been reported in raptors.

Histomoniasis is a protozoan disease.

Etiology

Histomonas meleagridis.

Hosts

Mainly disease of turkey but has also been reported in chickens, peafowl, grouse, quail and gallinaceous birds.

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.

The disease is worldwide in distribution and remains the major parasitic problem in the poultry industry. The problems occur principally in poultry maintained on deep litter.

Etiology

Coccidiosis of all classes of poultry is caused by one or more of the many species of coccidia of Eimeria species. In chickens nine main species are encountered. Eimeria tenella, E. necatrix, E. maxima, E. acervulina, E. mitis, E. mivati, E. hagani, E. brunetti and E. preacox.

Diseases caused by toxic metabolites of fungi are called mycotoxicosis. It affects man and animals including birds. Fungi which grow on feeds and grains in an unfavorable environment mostly cause mycotoxicosis in birds.

It is a fungal infection of skin and the term favus is used for the disease in poultry. The disease is world wide in distribution.

Etiology

Microsporum gallinae, a fungus. The fungus is zoonotic. Lesions of ring worm are produced in humans in contact with infected birds.

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.

Introduction

1. Serious outbreaks of thrush have been observed in chickens, pigeons, geese, turkeys, pheasants, quail, peacock and many other species of birds.
2. Candida albicans is the most commonly isolated fungus from the outbreak. Mucor spp. and Aspergilli were also found in some cases.
3. The outbreaks are associated with unhygienic conditions and nutritional deficiencies. Infection is more common in young birds up to 10 weeks of age. Morbidity is very high and mortality ranges from 10-75%. Clinical signs are not specific. Poor growth and ruffled feathers are only clinical signs.

Introduction

This is a disease mainly of the respiratory system affecting domestic poultry, wild birds and zoo birds. Systemic aspergillosis affecting visceral organs and other tissues of the bird’s body is also reported. Reports are also available on eye and brain infections.

WNV was first identified in the West Nile district of Uganda in 1937. Reported in Western Hemisphere for the first time in 1999, in New York City. The virus had until that time been found only in Africa, Eastern Europe, West Asia and the Middle East.