Coccidia

Causes

Coccidiosis is a disease caused by a protozoa. That protozoa sheds oocysts in the droppings of infected birds. If the conditions are damp, the oocysts can survive for a long time. When the oocysts sporulate, other birds can become infected. There are two species of Coccidia that can infect finches, to my knowledge: Eimeria spp, and Isospora spp. I frequently find Eimeria oocysts in new finch droppings. So far, I have never seen Isospora spp oocysts.

Coccidia is one of those problems that can sneak into your flock despite quarantine because it can hide for a long time in healthy carrier birds. Those carrier birds may eventually become sick under stressful conditions or they may never succumb.

Coccidia is usually not a problem in the wild because the birds are unlikely to consistently stop and eat at spots that are consistently infected with oocysts. While many birds do carry the organism, it never gets to the point where it is out of control and causes illness. Captive birds, however, eat and drink in the same locations every day. They easily become reinfected over and over again, allowing the quantity of organisms in their system to reach unsafe numbers (from Dr Danny Brown's book Under the Microscope).

Symptoms

I don't have personal experience with the diseased state. I have only found oocysts being shed in non-symptomatic birds. However, according to Agnes Rupley, DVM, in Manual of Avian Practice, symptoms include diarrhea and dehydration. I have also heard that infected chicks will likely die by about week 10 after hatching.

Prevention

Because the oocysts can survive for a long time in damp conditions, keeing the environment dry may help prevent spread of Coccidia organisms. This is easier done indoors than outdoors. In outdoor aviaries, it may be best to implement a control program with periodic treatment if Coccidia is a problem, as it may be impossible to keep the environment free of the organism.

I have read that the oocysts are resistant to disinfection with bleach, but they can be killed with high temperatures. Cleaning cages and equipment with boiling water may help get rid of the oocysts if recurrent infections occur.

Treatment

When I find a bird infected with Coccidia, I use the drug Baycox. Baycox comes in a clear liquid form that can be added to the water and is available from pigeon supply stores like Foys. The preparation I use is mixed by adding .05 cc to 2 cups of water (4 cc per gallon). This is given as the sole water source for 2 days. I have heard of aviculturists giving for as much as 3 days, but I have never attempted this, nor have I needed to. Amazingly enough, after two days of treatment, I no longer find any oocysts and the problem has never returned to any infected bird that I treated. I do disinfect all cages and cage equipment with bleach, hot water, and sunshine after treatment.

Sulfa drugs like Trimethoprim-Sulfa may also be prescribed to treat Coccidia infections. Baycox and Sulfa drugs are a type of anti-coccidial drug known as coccidiocidal drugs. Coccidiocidal drugs kill the organism, eliminating it from the bird's system. I believe this is the best approach for indoor birds where the environment can be kept dry, and all cages and equipment can be disinfected to prevent spread of infections.

There is an alternative to coccidiocidal drugs and that is coccidiostatic drugs. Coccidiostatic drugs do not eliminate the coccidia, but instead arrest the development of Coccidia so that it cannot shed oocysts for a period and so that it can be kept under manageable control so as to prevent the disease state. It is my understanding that this approach may be more desirable in environments where it is impossible to eliminate infection because the bird will just be re-exposed and re-infected rather quickly. Coccivet and CocciCare both contain Amprolium, which is usually regarded as coccidiostatic drug, but I have also found sources that claim it can be coccidiocidal as well if given long-term. However, if I had a bird that was ill from a Coccidia infection, I would either take to the vet for treatment, or attempt Baycox treatment indoors. When the bird is well, I would return it to the outdoor aviary and likely implement some control procedure, perhaps using a coccidiostatic drug.