Friday, March 8, 2013

NPIP Follow Up

I wanted to write a follow-up post to my NPIP post. I wanted to talk specifically about the diseases that the NPIP testing covers. I understand that not all states tests for all four of these diseases but I am sure that if you ask they will, it may cost a little more though. Here in Georgia they test for Pullorum, which is what all states that test for NPIP test for, but they also test for Avian Influenza, M. Gallisepticum, and M. Synoviae. I personally feel that it is very important for any person owning chickens, whether for pet, show or food, to have the NPIP testing done. It just gives you a little more peace of mind knowing that you have a healthy flock.

The following is just a brief explanation of the diseases and how they affect our birds and what can be done to treat them.

Pullorum Disease is caused by Salmonella pullorum. It has very high mortality rates for young birds and can also kill adults. It was once very common but has nearly been eradicated. Transmission is through the egg, direct and indirect contact. If the egg has been infected, via the hen having the disease, then death usually occurs within the first few days of life and up to 2-3 weeks after hatching. Affected chicks seek and huddle under a heat source, don’t eat, appear sleepy and will have whitish colored droppings caked up around the vent. Any that survive will become carriers and can pass the disease to their offspring. There are currently no antibiotics approved to treat infected flocks.

Avian Influenzas (Bird Flu) are caused by orthomyxoviruses. This disease is zoonotic, meaning that some forms are transmissible to humans. Many wild birds carry this disease in a form that does not cause illness. Domestic birds can contract the disease from wild birds and get extremely sick, to the point of death. Some forms have a mortality rate of nearly 100% and can kill an entire flock in as little as 48 hours. For more information you can visit the CDC’s page on Avian Influenza.

M. Gallisepticum and M. Sunoviae are both Mycoplasmas. They are bacteria but they are very unique in that they lack a cell wall and must have a rich medium containing serum to grow. This can make them different to treat as most antibiotics work by destroying the cell wall. They do not live very long outside of their hosts; usually no more than a few hours or days. They are vulnerable to most disinfectants.

M. Gallisepticum is a chronic respiratory disease in chickens and an infectious sinusitis in turkey. Other avian species are also susceptible to infection. It is the most pathogenic of the Avian Mycoplasma. It is found worldwide. It can be transmitted via direct and indirect contact as well as through the eggs of infected individuals. The infection may be dormant in the infected, hatched chick for days to months, but when the flock becomes stressed aerosol transmission occurs rapidly and infection spreads through the flock. The infection can also be carried on the clothing or boots of a person from an infected flock to a clean flock. This is why Biosecurity is very important. In many flocks the source of infection cannot be determined. Once infected, birds remain carriers for life. Infected birds may show no apparent symptoms or have varying degrees of respiratory distress, slight to marked rales, difficulty breathing, coughing and or sneezing. Infection rates are high, but death rates are low in uncomplicated cases. There may be nasal discharge along with frothiness in the eyes. The disease is generally more severe in turkey than in chickens. Infected birds may fail to reach peak laying ability, while broilers may not gain weight as normal. Treatment with tylosin, oxytetracycline or erythromycin is affective, among other antibiotics. Antibiotics are usually given via the feed or water for 5-7 days. There is a vaccine, but it must be approved for use by the state veterinarian.

M. Synoviae occurs most frequently as a subclinical infection of the upper respiratory track. Chickens and turkeys are the primary carriers but ducks, guinea fowl, geese, parrots, pheasants and quail are susceptible. It can be transmitted through the egg, but the rates are very low. The risk of transmission via eggs is greatest the first few weeks after infection of the hen. Transmission via direct and indirect contact is rapid. Symptoms can include slight rales, but generally no signs are seen. Outbreaks generally occur in young birds, those about 4-6wks. The disease can cause tendonitis and bursitis, and some birds may sit, become depressed and generally stay close to the feeders and waterers. Swelling of the hocks and foot pads may be evident. These symptoms are generally only seen in severely affected birds. The mortality rate is very low, less than 10% in most cases. Treatment is with one of the tetracycline antibiotics.

Both M. Gallisepticum and M. Sunoviae are respiratory diseases of chickens. I wanted to point out that they have the possibility of being transmitted through the egg, in the embryo. So you can buy chicks or hatching eggs and possibly bring these diseases into your flock. Your birds will be carriers for life once they have contracted these diseases. There is a chance that when your birds become stressed they will develop the symptoms of these respiratory diseases. There is also a chance that when you bring new birds into your flock they will contract these diseases and may become sick. The only way to know you are buying birds or eggs that are free of these diseases is to purchase from those who have had the NPIP testing and come back clean of all of these diseases. The testing is very easy and is not expensive; I feel it should be done by anyone interested in keeping a healthy flock.

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