Viral diseases of pigeons Prof Dr Wafaa Abd

Viral diseases of pigeons Prof. Dr. / Wafaa Abd El-ghany Professor of poultry dis. , Fac. Vet. Med. , Cairo Univ.

Viral diseases of pigeons I. 1. 2. II. 1. 2. RNA viruses: Single strand (SS) RNA: (Paramyxo and Corona virus). Double strand (DS) RNA: (Reo virus). DNA viruses: Single strand (SS) DNA: (Circo virus). Double strand (DS) DNA: (Pox, Herpes and Adeno virus)

Paramyxo Virus (PMV) infection

Epidemiology • Viral disease of pigeons characterized by nervous manifestations and respiratory signs. • The causative agent is paramyxovirus (PMV) 1 (single strand, RNA virus) which is mutant variant mesogenic strain of NDV. This virus differs from other strains of NDV serologically, biochemically and the diseases can produce. • All ages of pigeons are susceptible but serious problems occur in young's. The infection occurs year around but common in un-vaccinated pigeons flocks during the racing season.

Epidemiology • The disease is transmit through direct and indirect contact with infected birds. • Infection occurs through ingestion of contaminated food and water by the droppings or nasal secretions and inhalation of contaminated respiratory secretions. • Out-breaks can occur when free ranging pigeons come in direct contact with un-vaccinated flocks. • Free ranged pigeons are source of infection to captive birds.

Signs • Incubation period varied from 5 days to over 1 month. 1) Nervous manifestations: A) Tremors in the head and neck. B) Torticollis. C) Opsthtinous D) Wing and neck paralysis. E) Dropping of the head and neck. 2) Greenish watery diarrhea with haemorrhages in severe cases. 3) Respiratory signs is rare. 4) MB rate (20 -80%) and MR rate 90%.

Lesions 1. Hyperemia and congestion of the brain with petichael haemorrhages. 2. Septicaemic picture of all carcass. 3. Catarrhal enteritis. 4. Enlarged kidneys. 5. Haemorrhagic of pancrease.

Diagnosis • The sample could be taken from the faeces or respiratory secretions during acute phase of an infection. • Isolation, identification or detection of antibodies titers are similar to other PMV infection (as NDV).

Differential diagnosis • • • NDV. Paratyphoid disease. Pigeon Herps virus. Intoxication by OPC. Intoxication with heavy metals.

Prevention • Prevent contact between healthy and diseased pigeons. • Avoid mixing between different ages. • Free ranged pigeons should be restricted from the captive birds. • Pigeons return from a show or a race should be quarantined for 6 weeks. • Living attenuated vaccine (Hitchner and Lasota), using eye drop instillation (I doesn’t prevent he infection and virus shedding). • Inactivated vaccine used in squabs 3 -4 weeks age S/C at the lower third of the neck (0. 2 ml) and revaccinate at 6 months to 1 year, breeders take the vaccine 4 months before laying S/C.

Control • There is no specific treatment especially in adults and it depends on brain damage. • Supportive feedings and antibiotics to avoid 2 nd bacterial infection. • Emergency vaccination using Hitchner or Lasoa vaccine via eye drop method to protect healthy birds and reduce the level of morbidity and mortaliy. • Infected birds with signs should be removed from the flock and didn’t return to the flock until 6 -8 weeks after they become normal. (he virus could be shed in the faeces of recovered birds up to one month).

Pigeon Herps Virus (PHV) infection

Definition Pigeon herps virus infection (PHVI) is an infectious oesophagitis or inclusion body hepatitis of pigeons based on gross or histological lesions that can be associated with infections.

Etiology • Pigeon herps virus 1 (PHV 1) is called Columbid herps virus 1 that belongs to family alfa herpsviridae. • All of PHV strains are antigenically related, some strains are highly pathogenic (severe morbidity and mortality and others are apathogenic). • The virus could be isolated on BHK (Baby Hamster kidney) cell inducing cytopathic effect, also all avian cell culture are susceptible.

Epizootiology • Pigeons are susceptible o natural and experimental infection. • All pigeon's ages are susceptible o infection but young age (less than 6 months old) are more susceptible than adults. Susceptible pigeons can be infected through direct contact with the infected birds. • Mature birds are asymptomatic carrier to the virus and shed it in the faeces or respiratory secretions. • The large quantity of the virus is excreted from carrier birds from their throat during the breeding season and during squab gorging, so the squabs are easily infected just after hatching (carriers due to maternal immunity that protect them).

Signs I. 1. 2. 3. 4. 5. Young pigeons: Initial signs are mild rhinitis and conjunctivitis. Moderate to severe dyspnea. Small ulcerated areas at the mucus membranes of larynx, pharynx and at the mouth (beak) commisure. Depression, anorexia, swelling of the nictitating membrane. Diarrhea, polyurea and neurological signs.

Signs II. 1. 2. 3. Older pigeons: Sinusitis and intense dyspnea in case of complications with Trichomonus columbi, Mycoplasma species and other bacterial invaders. Most of birds develop mild or sub-clinical infection unless the bird is immuno-suppressed with other concomitant diseases or environmental factors (severe disease in case of complications). Most of infected birds are recovered with 1 -2 weeks.

Lesions 1. 2. 3. 4. 5. 6. Some birds show no lesions (depends on the virulence of the virus and susceptibility of the host). Mild to severe ulceration of the mucous membrane of the upper digestive tract and nasal mucosa. Hepatomegally and splenomegally. Congestion of he intestine and ulcerated necrotic areas on the mucosa of GIT. Ulcers with gray yellow diphtheritic membranes on the pharyngeal, oesophogeal and laryngeal mucosa. In case of complications the trachea may be obstructed with caseous material with airsacculitis and pericaditis.

Diagnosis • Pharyngeal swabs of the infected pigeons could be inoculated on CEF (chicken embryo fibroblast) cell culture. Organs as trachea, lungs and liver could be used also for isolation. • Virus characterization immunologically by immunoflurescence (IF). • Serological detection of antibodies by VNT or indirect IFT.

Differential diagnosis 1. 2. 3. 4. 5. 6. Chlamydiosis. Trichmoniasis. Salmonellosis. Wet form of pox. Adeno virus. PMV.

Control • Acyclovir will prevent some but not all herps virus induced disease. • Trisodium phosphonoformate an antiherps virus drug, will protect pigeons from clinical disease and latent infection. • There is currently no commercial available vaccine.

Pigeon Herps Encephalitis Virus infection

Pigeon Herps Encephalitis Virus infection • A herps virus was isolated from the brain of pigeons with signs of diarrhea, encephalitis (tremors, leg and wing paralysis and torticollis), and high mortality. • The signs are common in young pigeons. • Dead birds showed congestion and haemorrhges of the brain, liver, pancrease and intestine.

Other Herps Virus infection

Other Herps Virus infection • A herps virus that is antigenically distinct from Mark’s disease virus has been associated with neoplastic changes in pigeons.

Pigeon Circo Virus infection (PCVI)

Definition • Pigeon circo virus infection (PCVI) is a contagious disease affecting primarily young pigeons with mortalities approach 100%. The signs and lesions due to virus immunosuppression with subsequent infection with other secondary viral, bacterial, fungal and parasitic agents. • The causative agent is a member of circovirdae (non enveloped and single strand DNA virus). • The virus could not grow in ECE or in chicken kidney or chicken fibroblast cells.

Epidemiology • PCVI primarily affects young pigeons 2 months to 1 year of age. • Spread appears mainly horizontal. He most common route of spread is mixing of pigeons during racing.

Signs 1. Lethargy, anorexia, weight loss and poor racing performance. 2. Respiratory distress. 3. Diarrhea. 4. The virus infection is associated with other viruses (PMV, Pox, adeno and Herps virus), bacteria (E. coli, S. typhimurium, Mycoplasma spp. , Pasteurella spp. and Clamydia psittaci), fungal (Aspergilluys spp. And candida spp. ) and protozoal infection as Trichomonus spp. 5. Mortality rate is ranging from 0 -100% depends on the virus, age and secondary infection.

Lesions 1. Usually the lesions are related to he secondary infections. 2. Bursal atrophy is sometimes recognized.

Diagnosis • The definitive diagnosis is based on histopathology and electron microscopically. • Histological lesions found in lymphoid organs (bursa, spleen and caecal tonsils) include lymphoid depletion and intracytoplasmic inclusion bodies.

Control • • • Careful attention of hygiene and quarantine at birds shipping especially racers. Strict quarantine measures (2 -4 weeks) for newly acquired squabs when they recently introduced to he flocks. Treatment of secondary infections.

Pigeon Pox Virus infection

Pigeon Pox Virus infection • Pigeons may develop either cuteanous or diphtheritic form of pox virus. • This disease is discussed in fowl pox viral infection.

Pigeon Reo Virus infection

Pigeon Reo Virus infection • Reo virus has been recovered from the liver of pigeons with hepatitis and from the faeces of pigeons with diarrhea and dyspnea. • The virus is primarily shed in the cloaca. • Reo virus was recovered from 13% pigeons with diarrhea, tremors and weight loss.

Pigeon Corona Virus infection

Pigeon Corona Virus infection • A strain of IBV serologically related to a strain found in chickens was isolated from pigeons. • This flock developed signs of ruffled feathers, difficult breathing and mucous accumulation at the beak commissure. • The lesions are ulcers in the crop and oesophagus, fluid accumulation in the lower intestinal tract and mucous in the pharynx and trachea. • The virus was isolated from tracheal mucosa and cloacal swabs.

Pigeon Adeno Virus infection

Definition • Adenoviruses are associated with 2 clinical diseases in pigeons called classical adenovirus and necrotizing hepatitis adenovirus. • Adenovirus isolated from pigeons were group (I), serotype 2, 5, 6, 8, 10 and 12.

Epidemiology • Classical adenovirus is only occur in pigeons under 1 year of age (approximately 6 months), although necrotizing hepatitis occurs in pigeons through out the year and affecting all types and all ages. Infection mostly occurs orally and the virus is shed in droppings. • Necrotizing hepatitis induces massive hepatic damage in the pigeon lofts with sudden death.

Signs I. 1. 2. 3. 4. 5. 6. 7. Classical adenovirus: Depression. Foul smell slimy green diarrhea. Thirsty. Vomiting and Despnea. Polyurea and weight loss. Morbidity rate is 100% within 2 days, but the birds are recover within one week. Secondary E. coli causes severe diarrhea, emaciation, weakness and death.

Signs I. Necrotizing hepatitis virus: 1. Affected bird dies within 24 -48 hours with rate about 30 -100%. 2. Yellow liquid droppings. 3. Some birds not showing any signs.

Lesions I. 1. 2. 3. Classical adenovirus: Catarrhal enteritis. Greenish fluid in the crop. Greenish mucous in empty intestinal tract.

Lesions I. Necrotizing hepatitis virus: 1. Enlargement of the liver and spleen. 2. Yellow to Cupper gold patchy discolouration of the liver. 3. Mild reddening of the intestinal tract lining.

Diagnosis Classical adenovirus: • Characteristic diarrhea and vomiting in pigeons younger than one year. It should be differentiated from PMV, Salmonellosis and hexamitiasis. Definitive diagnosis is based on demonstration of intranuclear inclusion bodies in the liver and intestinal tract.

Diagnosis Necrotizing hepatitis adenovirus : • Characteristic Sudden death of pigeons of all ages without signs except a short episode of vomiting and diarrhea. The virus should be demonstrated in the faeces of infected pigeons by electron microscopy as isolation of the virus is difficult till now.

Differential diagnosis 1. 2. 3. 4. 5. 6. 7. • Intoxication. Streptococcus. E. coli septicaemia. Chlamydiosis. PHV. Reovirus. Salmonellosis. Differentiation through typical microscopic aspects of the liver (extensive necrosis) and histological sections (inclusion bodies).

Control • In case of classical adenovirus, rehydration of affected birds and control of complicating bacterial infections. • In case of necrotizing hepatitis, maintain excellent hygienic measures with good ventilation. • There is no specific measures is available to control or prevent adenovirus infection of pigeons.