Partridges and other related birds: Infection in the red-legged partridge, grey and chukar partridges, phaisans and other related gamebirds - Microbiological diagnosis


Information 27-08-2018.

During the last decades the natural populations of game birds have decreased in many areas. The strategy to obviate the lack of wild species has been to release the birds raised on farms to replop or to supply for the hunting sector. Among these species are the common pheasants (Phasianus colchicus); the red partridges (Alectoris rufa), gray (Perdix perdix) or chukar (Alectoris chukar); quail (Coturnix coturnix), pigeons of different species, ducks and geese. This process includes a phase of breeding and development in interiors, followed by an air conditioning phase in large aviaries located outside. When the birds are ready for release, they are released in the repopulation or hunting areas.

The release of farm-raised birds presents some risks that may imply a high rate of mortality in the reintroduced population, due to poor behavior when released, predation by mammals or birds of prey, less resistance to diseases that they can cause epidemic outbreaks of them and genetic differences between released birds and wild birds.

Among these birds, the partridges are highly appreciated by gourmets and hunters, so it is considered a very popular hunting bird. It belongs to the Gallinaceas, included in the Phasianidae family of which there are two genera: Perdix and Alectoris.

The gray partridge (Perdix perdix), is a natural bird of Europe, which has been introduced in many parts of the world, but has declined a lot in Europe since the second half of the 20th century. Among the causes of this decline include an accentuated decrease of the life of the chicks due to the use of pesticides, the loss of habitats due to intensive agriculture and the mechanization of the field, the lower hatching of eggs, and the increase of predation by raptors or some wild mammals.

The red partridge (Alectoris rufa) is native to the Iberian Peninsula and is presently present in the South and Center of France, and Northwest of Italy, as well as in Spain. Its population has also declined much as it has happened in Europe with the gray partridge. 

Due to the high demand of the partridge for hunting and the shortage of wild birds, captive breeding has developed a lot and today has a significant economic importance. It has been published that in France about 15 million are raised, of which 2 thirds are exported to the United Kingdom, Spain, Portugal and Italy. In France, 1.7 million were hunted in 1998. In 2010, 6 million were produced in France for the French market, of which 77 to 80% were of the red species. In Spain, it is estimated that 3 million are hunted per year, so it has a relevant socio-economic importance. 

The red partridge grows and reproduces easily in captivity if the proper hygienic and therapeutic conditions are taken to avoid diseases. This species is very sensitive to several pathogens that are responsible for 10 to 15% mortality and in some cases up to 70 to 80%, which means that some breeders sometimes decide to abandon their offspring. Death rates of 46 to 52% have been cited in these birds between 26 and 31 days of age. 

The red partridge reared in Spain, accounts for approximately 7% of global avian production. It is estimated that between 3 and 4.5 million red partridges are raised in the wild, and that the number released from breeding farms can be 10 million per hunting season. The lack of biosecurity measures in some of the red partridge farms, together with the limited control measures before or after release to the field, may favor the introduction, adaptation, maintenance and dissemination of pathogens. 

Birds from hatcheries on farms may introduce new agents into wild populations or suffer the adverse effects of the parasite load they contain. The release of pheasants or red partridge can also be harmful to the gray partridge, due to competition in the habitat or the transmission of pathogens.

There are several types of infections that can occur affecting one or other organs, sometimes with higher prevalence in some species than in others, and even within the same species or in any of the species, there may be differences according to the age of the species. birds in which the infection occurs. 

Virus infections

There are viruses that can cause infections in these birds, some of them that affect the nervous system, others to the respiratory system and others produce a general infection. Among these viruses are the following: Bagaza virus, West Nile virus, several types and subtypes of Influenza virus, Newcastle disease virus, Avian Poxvirus and Marek's disease virus. Then we describe some characteristics of these viruses and the affectations that they can cause in infected birds.


Bagaza Virus (BAGV)

This virus is synonymous with Israel's turkey meningoencephalomyelitis virus (ITV: Israel Turkey meningoencephalomyelitis virus), named for having been initially described in Israel in 1958. It is a virus transmitted by mosquitoes, belonging to the Flaviviridae family, genus Flavivirus, which causes a severe neurological disease in chickens and wild birds, making it an Arbovirus (Arbovirus: Arthropod Borne Virus). Some 7 years later (1966) of the description in Israel, the virus was isolated from a batch of Culex mosquitoes in the city of Bagaza (Central African Republic), showing that both were genetically identical, that of Israel and the city of Bagaza, The change of name was proposed by "Avian Meningoencephalomyelitis virus" (avian meningoencephalomyelitis virus) (acronym AMEV).

For a long time, the virus was restricted to sub-Saharan Africa (Central African Republic, Mauritania, Senegal and South Africa), Israel, and India, but in 2010 it appeared in Europe causing an outbreak that affected the red partridge (Alectoris rufa) and the common pheasant (Phasianus colchicus) in the South of Spain. With this outbreak it was demonstrated that it causes a high mortality in the red partridge, and that it can even be transmitted by contact between these animals. The studies carried out with the gray partridge (Perdix perdix) have shown that these birds also suffer from a serious disease with neurological signs and mortality of 40%. Serological studies have shown that the virus continues to circulate in Spain.

Experimentally, it has been shown that the virus affects the central nervous system, but also the vascular endothelium, causing an intense hemolytic process in partridges that does not appear in the other birds studied. The birds of the 2010 outbreak showed incoordination, disorientation and ataxia. Mortality was 37% in partridges and 11% in pheasants. Histopathological studies showed the existence of encephalitis, myocarditis, leiomyositis, meningoencephalitis and neuritis.


West Nile virus (West Nile virus -WNV)

West Nile virus is a neurotropic virus transmitted by arthropods (Arbovirus: Arthropod Borne Virus), belonging to the family Flaviviridae, genus Flavivirus. Its natural cycle involves several species of birds in which the virus multiplies and a wide variety of mosquitoes that transmit it to each other. These mosquitoes can also transmit the virus to horses or people, who may suffer from clinically manifest disease or be infected with an asymptomatic infection without suffering symptoms. Before the 1990s, it was considered a virus of limited importance in birds, but since then it has spread widely geographically and is now considered to be of worldwide distribution, having passed from Europe to the USA. where it has spread across all states.

Studies have been conducted on the red partridge (Alectoris rufa), as a native species of European birds, showing that infected birds develop disease with a mortality of 70% when infected with strains of European West Nile virus, but also that they are susceptible to the American virus strains with a mortality of 14 to 45%. The affectation depends on the age at which the birds are infected. The virus causes an encephalitis. Its pathogenesis has been studied in the chukar partridge (Alectoris chukar) and in the red partridge (Alectoris rufa), demonstrating experimentally that both species can be infected with the West Nile vius (WNV) strains of the Mediterranean. The most affected organs are the heart, brain, and spinal cord. However, the degree of involvement caused by the European strains of the virus seems to be lower than that caused by the American strains of the virus.

Newcastle disease virus (NDV) (Avian Paramyxovirus type 1)

Newcastle disease in domestic poultry is caused by infection with avian paramyxovirus type 1 (APMV-1: Avian Paramyxovirus type 1; NDV) of the genus Avulavirus family Paramyxoviridae. This is one of the two most important diseases of poultry and other birds worldwide, not only for the economic losses involved, but also for its health implications that include high mortality in the pens. However, the involvement by NDV can be variable, including from the absence of symptoms to an acute disease with high mortality.

Some variants, such as the so-called Paramyxovirus 1 of pigeons (Pigeon Paramyxovirus type 1 -PPMV-1) have been responsible for panzootias in pigeon farms. Outbreaks of this disease in pheasants (Phasianus colchicus) are not uncommon and it has been shown that they are very susceptible to NDV infection.

In 2006, an outbreak of Newcastle disease (ND) was described caused by PPMV-1 in a gray partridge farm (Perdix perdix) in East Lothian (Scotland). The affected birds suffered diarrhea, progressive neurological signs and a mortality of 24%. It was intuited that the infection was transmitted from nearby pigeons because the pigeon virus variants (Pigeon paramyxovirus type 1, PPMV-1) had been found.

Influenza A Virus

Avian influenza viruses (Avian Influenza virus -AIV-) have been isolated from many bird species. Among the most interesting for their breeding in farms are the following: turkeys, ducks, geese, quail, partridges, guinea fowl, pheasants, ostriches and chickens. Of these, the turkeys are especially susceptible and the first infection in them was diagnosed in Wisconsin (USA) in 1966. Also, it is of interest the fact that the quail can act as amplifier of recombinations of the virus, making subtypes that previously did not affect some species, such as humans or other mammals, can become infected after having passed the virus through the quail. The quail can allow the replication of most of the subtypes, as it happens with the pig and the subtypes H1 and H3 of the Influenza A viruses. In the same way, the quail is more susceptible than the chickens to the H9 viruses. , which suggests that adaptation of strains transmitted from waterfowl (ducks) can occur in them, and then infect other terrestrial birds. In this sense, the quail would act as the intermediary host species. This same fact, has been found in the partridges, so it is a kind of great interest for the spread of influenza A viruses.

Avian influenza viruses (AIVs: Avian Influenza viruses) according to the ability to cause disease and death in Most poultry species (eg, chicken - Gallus domesticus) can be classified into two different pathotypes: a) Low pathogenicity (LPAIVs: Low Pathogenic), and b) High pathogenicity (HPAIVs: Highly Pathogenic). Infections with LPAIVs can be asymptomatic, but in general, they cause a mild to severe respiratory disease, which is usually accompanied by a decrease in food and water intake and a drop in egg production. On the contrary, HPAIVs cause a serious systemic disease, with high mortality in chickens, but which does not imply the same degree of disease in other species.

Since the first isolation of an AIV from wild birds, an HPAIV H5N3, in a seabird (Sterna hirundo) in South Africa (1961), viruses of the subtypes corresponding to the 16 hemagglutinins and 9 different neuraminidases have been isolated from more than 100 species of wild birds belonging to more than 25 families, confirming that AIVs have a worldwide distribution in free-living waterbird populations.

Waterfowl, mainly those of the Order Anseniformes (ducks, geese, swans), have been recognized as the natural hosts and reservoir of all LPAIVs. These viruses are highly adapted to their reservoirs, usually producing asymptomatic infections and replicating in the gastrointestinal epithelial cells, with elimination of a high content of virus in their feces for prolonged periods. Therefore, it is considered that the fecal-oral route is the primary route of transmission of LPAIVs in waterfowl. LPAIVs can be found in many different birds other than their natural reservoirs, but it is not clear in which of these species the LPAIVs are endemic and in which the virus is a transient agent.

Unlike what happens with LPAIVs, HPAIVs are not usually found in natural hosts, but arise from LPAIVs H5 and H7 after circulating in gallinaceous poultry for a variable period of time. Therefore, the exposure of waterfowl viruses to poultry, either by direct contact with wild birds, by contact in live poultry markets, or through bird drink waters is critical to the emergency of HPAIVs.

Since 2002, panzootic outbreaks have been reported in domestic and wild Anseniformes of Asia and Eastern Europe. These evolved viruses are highly pathogenic (HP) in these species under experimental conditions, something that is unusual for HPAIVs. The usual pattern of excretion of HPAIVs H5N1 in waterfowl implies a low virus titer and for a short period. Chickens and turkeys (Meleagris gallopavo) are birds, which along with ducks, have been studied more extensively for AIVs.

Some studies suggest that turkeys are more susceptible to LPAIVs than chickens. This high susceptibility demonstrates the relevance of turkeys as intermediate hosts and source of infection for other poultry or even for mammals. In addition, turkeys seem highly sensitive to HPAIVs, with a dynamics of infection and pathological findings very similar to chickens. Experimental studies in turkeys and chickens show that LPAIVs are predominantly eliminated from the oropharynx, and in lesser amount by the cloaca, unlike what occurs with waterfowl, which act as natural hosts. A similar dynamic occurs with HPAIVs, although in a greater proportion than LPAIVs. To date, several experimental studies have evaluated the sensitivity for LPAIVs and HPAIVs in the main species (chickens, turkeys and domestic ducks), and wild aquatic birds.

Wild birds, particularly those of the orders Anseniformes and Charadriiformes, have been recognized as the natural reservoirs of AIVs. Some studies suggest that turkeys, pheasants and Japanese quail are more susceptible than chickens to Influenza A viruses transmitted from free waterbirds. Experimentally, it has been shown that HPAIVs can cause specific clinical signs and mortality in the species mentioned, and that pheasants are efficient eliminators of LPAIVs. In addition, free breeding of birds has been identified as one of the factors that contribute to the increase of outbreaks of AIVs.

So far, most experimental studies on AIVs have been conducted with chickens, turkeys or aquatic species, while studies on minor species are scarce and many aspects of the epidemiology of both LPAIVs and HPAIVs in poultry are unknown. of free breeding and game birds. There are almost no studies of sensitivity to the infection and pathogenicity of AIVs in the red partridge (Alectoris rufa). This important hunting species is widely distributed in the South West of Europe and in the South of the United Kingdom.

To know the affectation that the partridges can suffer, experimental studies have been carried out in the red partridge (Alectoris rufa) inoculated with both a strain of HPAIVS H7N1 (A / Chicken / Italy / 5093/1999), as with one of low pathogenicity H7N9 (A / Anas crecca / Spain / 1460/2008), demonstrating that they are very affected by the high pathogenicity strains (HPAIVs) in comparison with the low pathogenicity strains (LPAIVs). Affectation by the HPAIV strain damages the kidneys, adrenal glands, feather follicles and the central nervous system (brain and spinal cord) more intensely. Only the gonads, spleen, bone marrow and sciatic nerve showed no significant involvement.

            Poxvirus (Avian Poxvirus - Avipoxvirus)

Avian poxviruses belong to the family Poxviridae, genus Avipoxvirus and include several species each specific for different groups of birds. The species Fowlpox affects the gallinaceae. Other species are: Canarypox, Juncopox, Mynahpox, Pigeonpox, Psittacinepox, Quailpox, Sparrowpox, Starlingox and Turkeypox. All these species are characterized by avian pox, a clinical entity characterized by the development of cutaneous pustules in their hosts, and also by involvement of the oral mucosa and upper respiratory tract.

Unlike other viruses, Avipoxviruses can tolerate extreme dryness, an advantage that allows them to spread with dust and adapt to the dry mucous membranes of the upper respiratory tract of birds. Being very stable in the environment, transmission between wild birds can occur through mechanical transmission through mosquitoes or through small skin lesions that allow it to penetrate the skin.

Avian pox (Avian pox) is a contagious viral infection of worldwide distribution that has been described in more than 60 bird species of about 20 families, especially galliformes. Because of its importance, vaccination is usually carried out in many farms. However, the disease persists due to domestic poultry houses, where preventive measures are not taken and since these can be extended to wild birds. The current tendency to change production systems, doing so with birds in freedom, could mean an increased risk of outbreaks of smallpox. Despite the specificity of Avian Poxvirus species, infections of wild bird populations could pose a risk to chickens.

This virus can cause respiratory distress, decreased intake of food and drink by infected birds. External lesions are limited to non-feathery parts, in general the face and legs, where they generate lesions characterized by proliferative and necrotizing dermatitis. In addition, it can form bloody vesicles that collapse when pricking and draining. The virus induces high mortality in pheasants, quail and partridges, songbirds, seabirds such as seagulls, parrots and peregrine birds such as hawks. Mortality in free-living galliforms ranges from 2% to 54%, depending on many factors. In experimental studies it ranges from 21 and 27%.

The infection in the red partridge (Alectoris rufa) of free life in Spain is frequent. In the year 2000-2001, there was an outbreak of avian Poxvirus infection in the South of Spain, in which it was demonstrated that the affectation occurs with greater intensity of the young specimens, compared with adults.

            Marek's disease virus (MDV-1; Gallid herpesvirus 2 -GaHV-2)

Marek's disease is a well-known disease in poultry throughout the world and is caused by a herpesvirus (Gallid herpesvirus 2 -GaHV- 2), also known as Marek's disease virus serotype 1 (MDV-1). Since the introduction of a vaccine, its incidence has been greatly reduced but it is still diagnosed in unvaccinated chickens.

Apart from the chickens, the disease has also been described in turkeys, Japanese quail, pheasants, and more recently in the crested quail (Rollulus rouloul) in Belgium (2015). In the crested quail, it presents with lesions characterized by swelling of the periorbital area, as well as corneal and lens opacity that lead to blindness. Over a few months all the affected birds die.

            Toxin poisoning (botulinum toxin) - Avian botulism

Avian botulism is a paralytic disease caused by the ingestion of the toxin produced by Clostridium botulinum, an anaerobic, gram-positive, spore-forming bacterium. The toxin acts by blocking nerve function and as a consequence causing respiratory and musculoskeletal paralysis.

The affectation is due to the toxin and not to infection by Clostridium botulinum. There are several types of toxins produced by different strains of this bacterium. In birds, type C predominates and in a lesser proportion type E.

This bacterium is very distributed in the soil (soil) and only requires warm temperatures, a source of proteins and an anaerobic environment (without oxygen) to multiply and produce the toxin.

Decomposing plants and invertebrates (insects) combined at the right temperatures can provide the ideal conditions for this bacterium to multiply and produce the toxin.

Birds are affected when they ingest the preformed toxin directly or when they ingest invertebrates (eg, fly larvae, chironomid larvae - diptera similar to non-biting mosquitoes), which contain the toxin that does not affect them. In fly larvae, the toxin accumulates when they ingest it from carcasses of dead animals. Preferably, this occurs in waterfowl, which can be affected by botulism when they eat 3 or 4 fly larvae.

The disease is manifested by flaccid paralysis that usually occurs in the legs, wings, neck (can not keep the neck upright) and eyelids.

Brain Infections due to Listeria monocytogenes (encephalitis)

The genus Listeria is composed of 10 species, of which two of them have been related to infection in humans and animals. Listeria ivanovii infections are rare and restricted to ruminants. In contrast, Listeria monocytogenes infections are related to a variety of animal species and humans. Listeria monocytogenes has a universal distribution and is widespread in the environment. 16 serotypes are known but of them the most involved in diseases are serotypes 1 / 2a; 1 / 2b and 4b.

Interest in Listeria monocytogenes began in the 1980s when it was recognized as a significant foodborne pathogen causing human infections. Infections have been described in 17 avian species, including chickens, turkeys, ducks, canaries, parrots and others. However, listeriosis as a disease is rare, and outbreaks are sporadic with variable morbidity and mortality. Birds are difficult to infect and young birds are considered more susceptible. Listeriosis in birds usually presents as a septicemia with splenomegaly, hepatic and myocardial necrosis and pericarditis. Descriptions of Listeria encephalitis are rare and have occurred in chickens in the US, Japan and India. Birds affected with encephalitis usually show torticollis, depression and incoordination. These neurological signs cannot be distinguished from those manifested by Newcastle disease, which should be considered in the differential diagnosis of Listeria encephalitis. Scientific reports have described isolated cases of neurological involvement in partridges in France (1957) and an outbreak in the United Kingdom in red partridges (Alectoris rufa), with neurological affectations.

            Coccidiosis Infections

Coccidiosis is one of the most widespread diseases affecting birds in the world. It is caused by a highly specific parasitic protozoon Coccidia, of the genus Eimeria. Several of its species can specifically invade specific segments of the intestine of birds, where it penetrates the intestinal cells of birds, causing them enteritis, accompanied by diarrhea and occasionally death. This leads to significant economic losses in the intensive production systems of poultry. Currently, there is only prevention and some coccidiostatic drugs for its control. For this reason, the risk of resistance to treatment is high, as has been observed in game birds, and numerous outbreaks have been reported, which means that some breeders have given up raising game birds.

Birds reared on farms for repopulation or hunts can be carriers of coccidia such as Eimeria spp.

Studies conducted in Brazil indicate that there is no parasitization by Eimeria spp. in the chukar partridges studied (Alectoris chukar), unlike the quail (Coturnix coturnix), which did have mild parasitation.

The production of the red partridge (Alectoris rufa) can be affected by frequent enteric diseases such as coccidiosis that is associated with high morbidity and mortality in them.

Eimeria kofoidi, Eimeria caucasica and Eimeria legionensis have been isolated from the ejecta of the red partridge (Alectoris rufa), in which it is rare to find monospecific infections. In experimental studies, it has been shown that when monospecific infections are carried out it is difficult to cause mortality comparatively with non-inoculated controls, whereas when they are inoculated with the three species, a mortality of 28% can be achieved. The largest cecal lesions are obtained in birds infected with E. kofoidi and E. legionensis species. Each individual infection causes growth depression and even weight loss in birds inoculated with E. legionensis. Dual infections by E. kofoidi and E. legionensis, or triple infections, increase this effect.

Little is known of coccidiosis in red partridges. When oocysts of E. kofoidi (300,000 oocysts / partridge) are inoculated, intense lesions appear in the duodenum and jejunum, characterized by a thickened edematous mucosa and intestinal lumen filled with thick mucus, gas and sometimes false membranes by the detached epithelium. E. caucasica also invades both the duodenum and the jejunum, causing occasional haemorrhages of the serous surface as well as mucoid duodenitis and catarrhal enteritis when 30,000 oocysts per bird are inoculated. E. legionensis mainly invades the caecum, and low mortality is observed when 200,000 oocysts per bird are inoculated. Cecal walls thicken and caseous material condenses. For each species, the elimination of oocysts begins at 5 days postinoculation, reaches the maximum at 9, 8 and 6 days post-inoculum for E. kofoidi, E. caucasica and E. legionensis, respectively, and then decreases and persists for about 15 days postinoculation

Infections by Hexamita meleagridis (Spironucleus meleagridis)

Hexamita meleagridis (Spironucleus meleagridis) is a flagellated protozoan found in the intestine of a wide variety of poultry, including turkeys, chukar partridges, quails and peacocks, in which it causes a catarrhal enteritis infectious.

This parasite was first found in 1939 in quail and chukar partridges. However, most diseases related to Hexamita meleagridis come from turkeys. The infectious catarrhal enteritis due to H. meleagridis was a problem in the USA. and Canada during the first years of industrial breeding of turkeys between the 1940s and 1950s, and resulted in significant economic losses. From then on, the incidence of this disease decreased and very few cases have been described. In recent years, infectious catarrhal enteritis seems to have relapsed, with the increasing frequency of commercial operations of turkeys, and likewise, the ability of this parasite to cause a devastating disease in chukar partridges has been written. In an outbreak in 1999 and 2000 in California, the affected birds were between 4 and 6 weeks old, showing diarrhea, languor, depression and high mortality. In addition, most affected birds showed facial dermatitis, and legs, suggestive of a deficiency of B vitamins.

The flagellated protozoan can be found in the lumen of the duodenum and jejunum and in the intestinal crypts. In some cases, the flagellates are located between epithelial cells or localized intracellular cells within the mucosal epithelium and the lamina propria of the mucosa.

     Infections by Mycoplasmas (Mycoplama gallisepticum and others)

Mycoplasmas mainly cause upper respiratory diseases and they have been described in pheasants and quail in the United Kingdom and the USA. for many years. 

Mycoplasma gallisepticum, Mycoplasma synoviae, Mycoplasma meleagridis, and Mycoplasma iowae are considered the most important pathogenic mycoplasmas for chickens. The economic impact of mycoplasmosis in the production of chickens has been amply demonstrated, mainly in the sec of meat, where the conversion of food decreases and mortality increases. A new clinical disease associated with Mycoplasma synoviae has been reported, which is characterized by affecting egg layers by altering egg production and decreasing it.

Mycoplasma gallisepticum infection is characterized by conjunctivitis and sinusitis, sometimes accompanied by intense bilateral swelling of the eggs. the infraorbital sinuses. There may also be involvement of the lower respiratory tract. Affected birds lose capacity and morbidity is high, although mortality is variable, perhaps depending on adjuvant factors.

It has been shown that pheasants and partridges have many species of rapidly growing mycoplasmas in the upper respiratory tract. The role of these organisms in affectation is unknown, but their presence may mask the isolation of slow-growing species such as Mycoplasma gallisepticum or Mycoplasma synoviae.

Mycoplasma gallisepticum infection has been demonstrated in partridges. The affectation has been reproduced in experimental studies carried out in the USA. and the United Kingdom in chukar and red partridges with Mycoplama gallisepticum as sole infecting agent. Outbreaks of Mycoplasma gallisepticum infection, typical of chickens, have been reported in gray partridge farms in Moravia (Czech Republic).

Mycoplasma iowae is considered a specific pathogen of turkeys, although it occasionally infects other bird species, including chickens. Turkeys and chickens experimentally inoculated with Mycoplasma synoviae show lower growth, leg abnormalities, moderate air sacculitis and plumage alteration. In commercial breeding turkeys it has been observed that the most significant sign of their infection is an increase in the death of embryos. Other signs include poor growth, anomalies of the legs and bones, arthrosynovitis and moderate air sacculitis.

In gray partridges (Perdix perdix) it has been found that M. iowae can cause recurrent intestinal and respiratory alterations. In an outbreak described in 2011, respiratory and intestinal alterations were found in all ages with an average mortality of 20% (11.7% to 36.3%, higher for the younger age and indoor location, and lower in the older age and location outdoors). The most important manifestations were poor body growth, poor development of breasts muscles, anomaly in the development of the keel and bone fragility. Some birds showed infraorbital sinusitis with serofibrinous exudate and catarrhal tracheitis, while others had serofibrinous air sacculitis and splenomegaly.

Mycobacterial infections (Mycobacterium avium subsp. avium)

Avian tuberculosis is an infectious disease that affects many bird species throughout the world, although currently it seems to be more prevalent in birds found in zoo aviaries, captive birds, or in company.

The disease is associated mostly with Mycobacteium avium subsp. avium and, less frequently, other species of mycobacteria.

Avian tuberculosis is a chronic disease causing granulomas that appear most frequently in the liver, spleen, gastrointestinal tract and bone marrow.           

Microscopically, the disease can manifest itself in three ways depending on the affected species: the classic tuberculoid, focal or multifocal form; a diffuse form; or a paratuberculosis-like form in the gastrointestinal tract.

There are descriptions of involvement in red partridges that were in zoos and in wild birds. Also, an outbreak of tuberculosis by Mycobacyterium avium subsp. avium has been described in the scientific literature. avium in this partridge species in breeding farm.

Fungal infections

  • Systemic karyadiasis in red partridge. 
  • Mycotic proventriculitis in gray partridge by Macrorhabdus ornithogaster in breeding farms. 


Recommended tests for diagnosis and performed in IVAMI:

  • Virus infections: molecular diagnosis (PCR ). 
  • Botulinum toxin: see specific information. 
  • Infections due to coccidia or other intestinal protozoa: microscopic examination and molecular identification. Detection of intracellular phases in samples of intestinal mucosa through histopathological studies. 
  • Infections by bacteria or fungi: culture and molecular identification. 

Recommended sample:

  • Infections with neurological affectation (Bagaza virus, West Nile virus, Newcastle disease virus, Listeria monocytogenes encephalitis, ...): brain sample. 
  • Botulism: serum from live animals; coagulated blood of the heart, intestinal content of dead birds. 
  • Other types of infections: sample of the tissue where the infection is located. 

Conservation and sample shipment:

  • Refrigerated (preferred) for less than 2 days.
  • Frozen: more than 2 days. 

Delivery of results:

  • Molecular diagnosis of virus infections (PCR): 24 to 48 hours. This period can be increased if the detection of a large number of pathogens at the same time is requested. 
  • Botulism (see specific information). 
  • Coccidiosis: microscopic examination of feces to detect oocysts: 2 to 4 working days. 
  • Coccidiosis: examination of mucosal biopsies intestinal for intracellular phases: 5 to 7 working days; Examination of intestinal mucosal biopsies for intracellular phases and identification of species by molecular typing: 15 working days. 
  • Infections by bacteria or fungi by culture and molecular identification: 3 to 5 working days. 

Cost of the test:

  • Molecular detection of infectious agents such as viruses or others (PCR): consult 
  • Botulismo: see the specific information of this toxin. 
  • Coccidiosis: microscopic examination of feces to detect oocysts: consult ivami @ 
  • Coccidiosis: examination of intestinal mucosa biopsies for intracellular phases: consult 
  • Coccidiosis: identification of species by molecular typing: consult 
  • Infections by bacteria or fungi by culture and identification molecular: consult