Monday, 19 October 2015

5 Deadly Diseases that Affect Turkeys

A sick turkey

Each year several millions of turkeys are lost through diseases and infections. Young turkeys are especially susceptible to diseases because their immune systems are not well developed. This makes mortality in poults quite higher than in adult turkeys.  Diseases remain one of the critical topics in the poultry industry at large. Some diseases are non-fatal while others are deadly and can even be transmitted to humans.

Early detection of disease and proper diagnosis can make a lot of difference. It must however be stressed that an absolute diagnosis can only be made after a visit to the vet. Using only symptoms may confuse you because of the similarities in the symptomatic signs of several of the diseases.

Having mentioned that, let us examine five of the deadliest diseases that affect turkeys. The list is however not in any particular order.

1.       LEUCOCYTOZOON INFECTION

i)        Description: Caused by a protozoan, the Leucocytozoon Infection is a dreaded disease with very high mortality rate in poults. Adult turkeys with matured immune system may recover from the infection. The disease attacks the internal organs of the animal and may lead to internal bleeding. Affected organs may have lesions on them which may cause other serious infections. The disease may also affect the blood of the infected bird. Leucocytozoon Infection may lead to sudden death in the infected bird.

ii)       Causes: The disease is caused by the bite of the black fly. Infection is a cycle which starts with a bite of an infected turkey by a black fly. Leucocytozoon smithi, which is the host specific to turkeys, is sucked up by the black fly after biting the infected turkey. The parasite later develops and when the fly bites another turkey, new infection takes place. The infection is only possible when the parasite matures in the black fly.

iii)     Incubation Period: The incubation period for the parasite is approximately 1 week. Mortality may occur between 7 and 20 days after the incubation period.

iv)     Symptoms: Some of the symptoms of the disease include
(1)    Listlessness
(2)    Loss of appetite
(3)    Excessive intake of water
(4)    Stunted growth
(5)    Coughing
(6)    Tracheal sound
(7)    Signs of depression
(8)    Lack of coordination
(9)    Tiredness
(10)Decreased egg production
(11)Decreased egg hatchability

v)      Diagnosis: The vet may screen the blood of the entire flock to detect the presence of Leucocytozoon smithi.

vi)     Prevention: Currently, only the black fly is known to transmit the disease through its bite.  Controlling the population of the insect may reduce the risk of infection. Black flies are common at locations with running water. Steps should be taken to prevent the invasion of the insect when the farm is located near such a place.

 In places where the population of the black fly cannot be controlled, preventive medication can be used to protect the flock.  Drug manufacturer, Merck, recommends that pyrimethamine (1 ppm) and sulfadimethoxine (10 ppm) added to the feed may be effective.

vii)   Treatment: There is no known effective treatment for the disease currently.

2)      HEXAMITIASIS

i)        Description: Caused by the flagellate protozoan Hexamita meleagridis,  Hexamitiais affects poults and is very rare in adult turkeys. Mortality is very high in poults between the ages of 3 and 8 weeks. Recovered birds build resistance to the disease but they may continue to be carriers of the parasite for the rest of their lives.

ii)      Causes: Chicken remains the number one carrier of the parasite. The protozoan is passed to other flocks through the droppings of the infected bird which may come in contact with the food or water of the flock.

iii)    Incubation Period: The animal begins to show symptoms of the disease 4 to 5 days after getting infected by the parasite.  

iv)    Symptoms: Some of the symptoms of the disease include
(1)    Ruffled feathers
(2)    Chilled
(3)    Prolonged chirping,
(4)    Listlessness
(5)    Huddling
(6)    Nervousness
(7)    Convulsion
(8)    Comatose
(9)    Loss of appetite
(10)Extreme thirst

v)      Diagnosis: Scientific analysis of intestinal mucosa may confirm the presence of the protozoa.

vi)    Prevention: Separate poults from the adult flock. This may reduce the transmission of the disease from carrier adults to the poults. Feed and water should be placed at a higher level to prevent droppings getting into them. Chicken should be isolated from the flock. Medication like histomonastats also helps to prevent infection.

vii)  Treatment: Mixing 0.22% Oxytetracycline in a feed for two weeks helps to prevent secondary infection. Alternatively, 0.022–0.044% of chlortetracycline in feed for two weeks also serves the same purpose.

3)      Fowl Cholera

i)        Description: Fowl cholera is caused by the bacteria Pasteurella multocida. The parasite is mainly found in the soil and affects turkey birds aged 6 weeks and older. Death is sudden and recovered birds may be carriers of the bacteria for life.

ii)      Causes: The parasite can survive in several hosts including domestic cats, rodents and wild birds. Turkeys may become infected when they eat infected feces in water or feed.

iii)    Incubation Period: Symptoms of the disease will manifest 5 to 8 days after infection.

iv)    Symptoms: Some of the symptoms of the disease include
(1)    Mucus discharge from mouth
(2)    Diarrhea
(3)    Anorexia
(4)    Pneumonia
(5)    Depression
(6)    Ruffled feather
(7)    Fever
(8)    Lethargy
(9)    Dark blue skin
(10)Excessive thirst
(11)Nasal cleft

v)      Diagnosis: Vets may test for the presence of Pasteurella multocida in infected tissues.

vi)    Prevention: Infected birds should be culled and the brooding place thoroughly disinfected. The parasite cannot survive disinfectants and direct sunlight.  

Carriers like rats, cats, dogs and wild birds should be controlled. In healthy flocks, live vaccines can induce immunity against the bacteria.

vii)   Treatment: 0.04% tetracycline in water or feed is effective against fowl cholera. Norfloxacin effectively treat symptoms of the disease.

Sulfonamides such as sulfaquinoxaline sodium can also be used to treat the infection. However when treatment is discontinued, mortality returns. This is an indication that treatment does not effectively eliminate the parasite.

4)      Turkey Coronavirus

i)        Description: Turkey Coronavirus is a gastrointestinal tract disease. The disease is highly contagious affecting the bird at all ages. Mortality however is higher in poults than in adult turkeys.  Mortality rate can be as high as 90% in poults. Recovered birds remain immune for the rest of their lives.

ii)      Causes: Carrier birds may pass the virus in their droppings. When the infected dropping is eaten by a bird, the animal will become infected. In about 72 hours, the infected turkey can also pass it through its droppings.

iii)    Incubation Period: The disease has very short incubation period. After ingesting an infected dropping, the bird may start showing symptoms between 18 and 24 hours.

iv)    Symptoms: Some of the symptoms of the disease include
(1)    Low body temperature
(2)    Diarrhea
(3)    Weight loss
(4)    Loss of appetite
(5)    Dehydration
(6)    Depression
(7)    Stunted growth

v)       Diagnosis: Scientific analysis of the intestine will determine the presence of the virus. The virus needs to be isolated and accurately identified from other enteric causing parasites.

vi)    Prevention: There is no known vaccine for the infection. Droppings of recovered birds may still contain the virus. It is therefore important to properly keep the feed and water to prevent transmission of the virus. The brooding place should be kept clean and overpopulation should be avoided.

Contaminated brooding places should be emptied and thoroughly disinfected. The place should remain empty for up to 4 weeks to ensure total viral elimination.

vii)  Treatment: There is no known cure for the disease. However alternative therapies include the administration of antibiotics, milk suspension mixed with potassium chloride and copper sulphate.

5)      Avian Influenza

i)        Description:  Turkeys are very susceptible to this viral infection. Avian Influenza is caused by a highly mutated virus with 256 variations. The deadliest of the strain is the HPH5N1 which can also affect humans. Another strain of the virus, H1N1, is more famous for the 2009 world flu pandemic that resulted in the deaths of about 17,000 people worldwide(World Health Organization).

ii)      Causes: Wild birds carry the virus and transmission is through oral and respiration. The virus can survive in viable environment for several months. Recovered birds can still excrete the virus in their droppings several weeks later.

iii)    Incubation Period: Incubation period for the disease is between 2 and 17 days.

iv)    Symptoms:
(1)    Diarrhea
(2)    Facial swelling
(3)    Dehydration
(4)    Lesions
(5)    Respiratory problems
(6)    Hemorrhages throughout the body
(7)    Listlessness

v)      Diagnosis: Diagnosis is by the examination of a dead bird for the presence of the virus.

vi)     Prevention: Wild birds are the major carrier of the virus. The brooder should be kept securely from wild birds. Roaming birds should be protected from coming into direct contact with wild birds.

Infected birds should be depopulated from the flock and a report should be made to the regulatory authority in your country. Infected broody houses should be thoroughly disinfected before new birds can be moved back in.

Vaccines are available but require approval from regulatory authorities before use.

vii)   Treatment: Current laws in several countries require outbreaks to be reported. Infected birds are usually culled.


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