Infections in falcons: Main infections - Microbiological diagnosis

Hawks can suffer from a large number of infectious diseases. Most infections are acquired from their prey (birds, arthropods, etc.). In hawks kept in captivity the feeding with chicks, pigeons, ducks, turkeys, or other birds, can be the source of their infections. It is possible that wild falcons may have acquired immunity that makes them resistant to some infectious agents.

Infections that can affect hawks can be caused by viruses, bacteria (including mycobacteria, mycoplasmas or chlamydia), fungi, protozoa, helminths or arthropods (ticks, mites, red mite of chickens -Dermanyssus gallinae-, feather mites, epidermis mites, feather lice, or feather flies In the case of external parasitization by the red mite, it may not be observed if the birds are observed during the day, because they usually hide in the environment and only parasitize during the night.

Among the viruses: Poxviruses (Raptorpox, Avipox falconi), Influenza A virus, Newcastle disease virus (Paramyxoviridae, Avulavirus), Hawk herpesvirus, ...

Among the bacteria are important Escherichia coli, Chlamydophila psittaci (≈ Chlamydia psittaci), Salmonella spp., Mycoplasma spp., Mycobacterium (avian tuberculosis).

Among the fungi are Aspergillus fumigatus (aspergillosis), or Candida albicans (candidiasis).

Among the protozoa, Trichomonas gallinae, Coccidios (Caryospora spp.), and Babesia spp. (babesiosis)

Among the helminths, it can be infected with trematodes (flukes), cestodes (tapeworms) and nematodes (Capillaria spp., Ascaris spp., Seratospeculum spp.).

Helminths (trematodes, cestodes, nematodes), as well as protozoa, are considered internal parasites because they cause intestinal and pulmonary infections, mainly.

The aforementioned arthropods are considered external parasitosis producers because they affect the feathers or the skin. Ticks and mites cause anemia and lice cause skin irritation and damage to the feathers. Feather flies can damage plumage and prevent flying.

The most common infections are the following: 

Trichomoniasis (Trichomonas gallinae)

It is one of the parasitic diseases best known in hawks, produced by the protozoan Trichomonas gallinae. This protozoan is a cosmopolitan parasite of pigeons, but it can affect other birds (chickens, wild or domestic turkeys, raptors, ...). In the birds causes a picture called "Mounth Canker" (gangrenous mouth sore). It is usually found in the oral or nasal cavities or in the upper parts of the digestive tract (esophagus) or the respiratory tract (trachea). This protozoan multiplies by binary fission and does not form cysts so they die soon after being eliminated by the host. It can be transmitted in three ways: a) between the pigeons when the infected feed the young with food secretions ("pigeon milk"). Adult pigeons do not usually have symptoms for one or more years and are a constant source of infection for their young; b) chickens and turkeys are usually infected through drinking water, contaminated from pigeons, or other birds; c) birds of prey, such as hawks, become infected when they are fed with other infected birds, for example, chicks or pigeons. In cases of acute infection there are few manifestations and they die suddenly. In other cases, as with infected chicks, they often stop eating, lose weight, cannot stand upright, or are unable to maintain balance. Sometimes they have diarrhea and death occurs after about three weeks of infection. The affected birds accumulate a greenish or cheesy exudate in the mouth that exudes from the beak. Yellowish-white nodules may be seen in the oral cavity or esophagus. The infection can be confirmed with laboratory tests in the greenish or oral cheesy exudate. For its control it is recommended to feed raptors in captivity with pre-frozen pigeons to destroy Trichomonas, and in case of infection to treat affected birds (antiprotozoals such as metronidazole, dimetridazole or carnidazole). 

Coccidiosis/Coccidiasis (Caryospora spp.)

Coccidiosis are Coccidia infections, are infections by acomplex and diverse group of parasitic protozoa from many animal species that in most cases cause no symptoms as hosts are immunized and animals recover unless they are reinfected. There are several families and the most frequent species of Coccidia are included in the family Eimeriidae, genera Eimeria, Isospora and Caryospora. The two species that usually affect raptors are Caryospora neofalconis and Caryospora kutzeri. These protozoa develop their life cycle in the cells of the intestinal mucosa and it is rare that they affect other internal organs such as the liver or kidneys. When there is disease, it is due to the large number of cells affected by the juvenile forms of the parasite, causing the destruction of intestinal cells in massive infections, with the consequent interference with feeding, altering the digestion or absorption of nutrients, causing dehydration, anemia and greater susceptibility to other infections. The manifestations are more frequent in young animals. In raptors infection is considered transmitted through the consumption of pigeons. The infection begins with the ingestion of the forms of resistance, oocysts. The oocysts contain inside the infecting forms (sporozoites) that when released into the small intestine penetrate into the enterocytes of the intestinal mucosa, giving rise to an asexual schizogonic cycle with the development of merozoites, which successively multiply, release and infect new cells. At some point the merozoites evolve into sexual forms, microgametocitos and macrogametocitos, giving rise to a sexual or gametogonic cycle. The micro- and macrogametocitos when undergoing a meiotic reduction are transformed into microgamets and macrogamets that are fertilized and transformed into a zygote. This zygote will mature and generate the sporoblasts, which will eventually mature into sporozoites, and will be surrounded by a cover, giving rise to the oocysts that are eliminated with the host's feces. 

Helminthiasis (nematodes, cestodes, trematodes) 

The main nematodes that affect them are Capillaria spp, Serratospiculum spp., and Ascaris spp. The parasitations by Capillaria spp. are frequent in raptors, parasitizing intestines, esophagus and oropharynx. Serratospiculum seurati, Serratospiculum tendo or Serratospiculum amaculatum, are located in air cavities. Its parasitization is acquired through the ingestion of some insects (beetles) infected with larval forms, which act as intermediate hosts. When ingested by the hawks, the larvae present in the beetles are released by being digested in the stomach, passing through the internal cavities until reaching the lungs where they mature to become adult helminths. When adults mature and copulate they deposit eggs that are expelled with respiratory secretions to be eliminated to the outside, or be swallowed and appear in the feces. The beetles would ingest the larvae coming from the eggs and in their interior they would become infected larvae. The infection by Serratospiculum spp., may not manifest itself clinically and these nematodes can live in the air cavities for years, but when the helminths die they cause a generally fatal aerial sacculitis. Trematode infections (flukes) are quite common but do not usually manifest symptoms. They can be located in the small intestine or in the bile ducts. Cestoda infections do not usually cause clinical symptoms because they are very adapted to their hosts, unless there are massive infections, in which case they can cause weakness or small bowel obstruction. 

Bacterial infections 

Gram-negative bacteria, such as Enterobacteriaceae, which are common in the small intestine of mammals and some bird species, are not usually present in raptors. Escherichia coli is considered an indicator of intestinal infection in hawks. Several serogroups and strains with different types of enterotoxins have been found. 

Other less frequent infections 

Babesiosis (Babesia spp.): This infection is transmitted by infected tick bites, so it can be avoided by controlling parasitization by ticks, as well as controlling the presence of ticks in the hawk's habitat.

Tests carried out in IVAMI:

• Escherichia coli: quantitative culture and identification, including detection of toxin production.

• Trichomoniasis (Trichomonas gallinae): Molecular diagnosis (PCR).

• Internal protozoa parasites (Coccidia -Caryospora neofalconis, Caryospora kutzeri) and helminths (nematodes, cestodes and trematodes): stool concentration followed by microscopic exam.

• Internal microsporidia parasites: Molecular diagnosis (PCR).

Recommended samples for the tests requested:

• Trichomoniasis -Trichomonosis (Trichomonas gallinae): sample of respiratory exudate taken with dacron or rayon swab (we can send the swabs by mail to your attention).

• Escherichia coli: fresh stool samples, collected in a sterile container.

• Internal parasites by protozoa (Coccidia -Caryospora spp., -) and helminths (nematodes, cestodes and trematodes): sample of fresh faeces, collected in a sterile container.

Conservation and shipment of the sample:

• Refrigerated for less than 2 days. You can send them in expanded polystyrene container (white cork) with frozen packs by courier to our address. 

Delivery of results:

• 48 to 72 hours on working days.

Cost of the requested tests received individually:

• Escherichia coli by quantitative culture: consult ivami@ivami.com.

• Escherichia coli toxin producer, by molecular methods by PCR for the detection of the genes coding for toxins: consult ivami@ivami.com.

• Trichomonas gallinae by qualitative PCR: consult ivami@ivami.com.

• Protozoa and intestinal helminths (internal parasites) by stool concentration and microscopic examination: consult ivami@ivami.com.