Latin America has an outstanding position in the world poultry industry, so it is necessary to know which are the most relevant poultry pathologies at present.

Peru is the country in the region with the highest per capita consumption of poultry meat, with one person consuming 51.1 kg per year in this country. In second place is Argentina, in third place, Bolivia, Brazil in fourth place and Panama closes the TOP 5 consumers.

On the other hand, Mexico is the dominant country in Latin America in terms of egg consumption, on average one person consumes 378 units per year. In second position is Colombia with 291 units, followed by Argentina, Uruguay and Chile.

In terms of production, the largest producers of both eggs and broilers in Latin America are Brazil, Mexico, Colombia and Peru. Considering this, it is a region of great participation in the local and global markets of the poultry sector. Therefore, it is of great interest to know the status of the most relevant diseases affecting these countries.

Viral, bacterial and parasitic diseases play a key role in poultry production, international markets, product prices and production costs, the sanitary status of a region and production efficiency.

Viral diseases of importance in Andean countries

There are many viral pathogens that affect both laying and broiler production poultry. The sanitary status of each country is variable thanks to the control and eradication programs that each country carries out permanently.

However, many of these diseases continue to circulate in the environment, generating important outbreaks that lead to economic and productive losses.

Marek’s disease

Marek’s disease is a viral disease caused by a Herpesvirus which develops a neuropathic and lymphoproliferative picture. This virus encodes an oncogene (Meq) which produces CD4 T-cell lymphomas, causing immunosuppression and development of metastatic lymphomas.

Vaccines have had a reduction in their efficiency in recent years. However, unvaccinated birds that acquire Marek’s disease are more likely to die.

Diagnosis of Marek’s disease is made by histopathology, immunohistochemistry and molecular testing to identify the strain involved.

Gumboro disease

Gumboro disease also called bursal disease is caused by an Avibirnavirus that has immunosuppressive effect in birds. This alteration of the immune system predisposes birds to secondary infections, decreases the efficiency of vaccines and is difficult to control.

This viral disease is highly contagious in young birds that still have the bursa of Fabricius. It has mainly two clinical forms: acute form that has a rapid course and high mortality, and subclinical form that has no clinical signs, but generates immunosuppression.

The diagnosis of Gumboro disease is made by clinical history, the presentation of signs and the use of laboratory tests such as RT-PCR and ELISA.

Avian Influenza

Avian influenza is one of the diseases of major control and surveillance in the world due to its zoonotic component and public health risk. There are strains of low and high pathogenicity that develop different symptomatology.

This virus belongs to the Orthomyxoviridae family, which is classified according to its hemagglutinin and neuraminidase.

The most common strain is of low pathogenicity whose signs are mild respiratory signs such as coughing and sneezing. However, the highly pathogenic strain can cause 100% mortality in birds. The signs observed are respiratory, leg hemorrhages, multifocal necrosis, edema and tachypnea.

For accurate diagnosis, RT-PCR and viral isolation tests are required. ELISA and agar gel immunodiffusion tests are also used for monitoring.

Newcastle disease

Newcastle disease is caused by a type 1 avian paramyxovirus. The severity of clinical signs depends on the virulence, tropism (predilection of the virus for organs or tissues) and pathotype involved in an outbreak.

In this viral disease there is a viscerotropic form where the virus causes lesions at the level of the gastrointestinal tract. In these tissues the virus causes ulcers, edema and hemorrhages in the mucosa of these organs, severely affecting their function. This produces diarrhea characteristic for its bright green or bloody type.

Newcastle disease is classified according to its virulence into high and low, and according to its pathogenicity into velogenic, mesogenic and slowogenic. In addition, there may also be infections in nervous and respiratory tissue.

Viral isolation and RT-PCR with sequencing methods are used for diagnosis. Serological tests are also used.

Infectious bronchitis

Infectious bronchitis is a viral disease of productive poultry caused by a coronavirus of the genus Gammacoronavirus.

This disease, as its name indicates, mainly affects the respiratory system of birds because the viruses bind to protein receptors that have sialic acid. Precisely, these receptors are in ciliated epithelial cells such as those found in the respiratory system, which leads to the loss of these cells and their defense function.

The signs observed at the respiratory level are congestion, presence of edema and mucus at the respiratory level, desquamation and necrosis. The lesions generated can lead the birds to present dyspnea and asphyxia, with subsequent death. In addition, infectious bronchitis can also cause lesions at the renal level due to damage to the tubules and renal nephron, worsening the health of the birds.

The reproductive system can also be compromised by lesions in the oviduct, which seriously affects egg production, since the virus affects the quality of the eggshell.

Bacterial diseases of importance in Andean countries

Salmonellosis

Salmonella is one of the bacteria of highest interest in the poultry industry due to the diseases it generates. Avian salmonellosis is a topic of public health importance because it is a zoonosis and a foodborne disease. In addition, it can generate serious clinical pictures that cause lesions in the digestive tract of birds.

In young birds, decreased growth, increased morbidity and mortality, diarrhea and reduced egg production are observed. In addition, Salmonella pullorum causes septicemia in young birds and Salmonella gallinarum affects adult birds at a productive level.

For the diagnosis of Salmonellosis, diagnostic tests of microbiological culture, ELISA test and molecular diagnosis by PCR should be performed.

Pasteurellosis

Poultry pasteurellosis generates the disease called fowl cholera, which has a septicemic clinical form. This pathology is caused by Pasteurella multocida which generates high morbidity and mortality.

Among the signs observed are ataxia, weakness, feather damage, anorexia, mucous discharge, cyanosis, diarrhea that changes color and consistency.

Clostridiosis

This bacterial disease is caused by the genus Clostridium. This bacterium is a common inhabitant of the digestive tract of birds that, under certain conditions, proliferates pathogenically and causes gastrointestinal lesions.

Clostridiosis generates necrotic enteritis characterized by severe lesions of the intestinal tract due to the release of toxins by the bacterium. These toxins generate direct damage to the intestinal barrier, predisposing birds to secondary infections and hemorrhages.

Coccidiosis: the most relevant poultry parasite in Latin America

Coccidiosis is a parasitic disease of poultry caused by protozoa of the genus Eimeria. These parasites carry out their life cycle in the cells of the poultry intestine generating a gastrointestinal disease.

Eimeria species commonly involved in poultry are E. acervulina, E. maxima, E. tenella, E. necatrix and E. brunetti that generate productive losses due to lesions in the intestinal epithelium. These enterocytes have a damage in the villi which reduces their capacity to absorb nutrients, even to the point of death of these cells in cases of severe parasitism. This damage to the villi prevents nutrient absorption, produces water loss, hemorrhage and predisposes to the development of bacterial infectious diseases. Signs observed are diarrhea, dehydration, feather disorders, anemia and reduced production in laying hens.

It has been reported that layer pasture systems are more likely to have outbreaks of coccidiosis. This type of grazing is common in multiple regions of Latin American countries in low-scale production. In these cases, the conditions of high humidity, contamination from wild bird feces and free-living cycle allow the proliferation of coccidiosis.

Preventive measures against poultry pathologies

The diseases reviewed here affect a wide variety of poultry organs and physiological systems. Therefore, production can be affected from multiple causes and mechanisms. These diseases of complex control can be controlled through alternative preventive measures that improve the welfare and health status of the birds.

In the case of the last-mentioned disease, coccidiosis significantly affects the absorption of nutrients due to the lesions it generates in the digestive tract.

For the control of this disease, Alquernat Zycox optimizes the intestinal mucosa by stimulating the local immune system of the digestive tract. This Biovet S.A. product contains intestinal optimizer pronutrients that improve the physiology and immunity against coccidiosis by interrupting its infectious life cycle. In this way, Alquernat Zycox prevents coccidia parasites from entering the intestinal cells, which avoids damage in the mucosa and its absorption processes. Additionally, this product works as a complement and even as a replacement in the use of coccidiostats or anticoccidial vaccines.

On the other hand, Alquernat Nebsui promotes the regeneration of enterocytes and reinforces the tight junctions between these cells, which improves the absorption processes in the digestive tract. This Biovet S.A. product contains intestinal conditioner pronutrients to replace growth promoters. This effect on absorption allows the animals to obtain a better nutrition and use of the elements provided in the feed, and therefore a better physiological and health condition against potential pathologies of importance in poultry farming.

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Situation of poultry pathologies in Latin America

Colombia

In Colombia, reports indicate that the cycle of Marek’s disease is unknown, but the presence of the virus in the field has been reported affecting laying hens and broilers.

Regarding Gumboro disease, the presence of a very virulent strain has been reported in Colombia, which causes mortalities between 60-100%. It has been reported that this virus in Colombia affects both laying hens and broilers by reducing their weight gain, decreasing egg production, increasing morbidity and causing meat seizures.

Currently, Colombia is a country whose recent reports indicate that there is no presence of avian influenza or Newcastle disease thanks to prevention efforts.

Brazil

In Brazil, Infectious Bronchitis has generated economic losses in breeding hens valued at USD 3567 in 25-week-old birds and USD 4200 in 42-week-old birds per 1000 birds evaluated. On the other hand, losses in 48-day-old broilers have been estimated at USD 266 per 1000 birds evaluated. These losses have been associated with the use of vaccines whose stimulation of the immune response has not been enough to immunize the birds.

International studies have estimated losses of US$ 1632 million in Latin America due to highly pathogenic avian influenza, mainly in Brazil and Mexico. As for countries in the Andean region, these costs would be USD 100 million.

Peru

In Peru, there have been reports of Marek’s disease in wild birds near Lima productions whose strains were of lentogenic origin. On the other hand, the presence of infectious bronchitis has been reported in Peru in the northern area of Lima.

Conclusions

Poultry farming in Latin America is a sector of great importance for the countries of this region and participates in a large proportion of the world market. Therefore, this continent is also subject to the presence of poultry diseases of viral, bacterial or parasitic origin. These diseases have a significant impact on production, the economy and the health status of the countries.

Among the most important viral diseases are Marek’s disease, Gumboro disease, avian influenza, Newcastle disease and infectious bronchitis. These diseases affect many tissues and have variations in the severity of their clinical course.

On the other hand, bacterial and coccidia infections are also of high impact in the poultry industry. These diseases are of great importance because of their clinical, productive and welfare impact. For these reasons, it is of great interest to know the current situation of the main poultry producers in Latin America.

References:

• Biovet S.A (2022). Alquernat Zycox P y L. Disponible en lĂ­nea: https://biovet-alquermes.com/producto/alquernat-zycox/
• Lopez, S., Villar, D., & Chaparro, J. (2019). Retos en el diagnĂłstico y control del virus de la enfermedad de Marek en Colombia. Revista MVZ CĂłrdoba, 24(1), 7157-7165.
• Soriano Pazos, J. A. (2017). Análisis y control de un brote de infecciĂłn con virus de bronquitis infecciosa aviar en aves vacunadas de una granja tecnificada de Lima.
• Ventocilla, K., Gonzales, R., & González, A. (2011). Presencia del virus de la enfermedad de Newcastle en aves silvestres de una laguna albufera cercana a Lima. Revista de Investigaciones Veterinarias del PerĂş, 22(1), 39-44.