Infectious Diseases of Poultry Production


Keeping poultry in wet, dirty, and crowded poultry houses without litter, but with the presence of drafts, poor and untimely feeding and watering weakens the birds and creates favorable conditions for the development of diseases. Basically, all poultry diseases in one way or another are connected to the violation of care and poor or inadequate feeding. Everyone knows that it is easier to prevent diseases than to treat them. According to the previous statement, people should pay special attention to disease prevention. Infectious diseases are considered the most dangerous among all poultry diseases as when they occur all poultry contained on a farm is affected. The purpose of this paper is to study ten infectious diseases and how they affect poultry.

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Salmonella is an infectious disease that manifests in form of lesions of the gastrointestinal tract and septicemia. In chronic cases, it is accompanied by pneumonia and arthritis. The cause of this disease is an infection of poultry with Salmonella bacteria (Figure 1). In the book Controlling Salmonella in Poultry Production and Processing, it is noted that Salmonella species grow best at temperatures between 35o C and 42o C (Russell, 2012, pp. 1-2). Poultry that have been ill with salmonella are still carriers and a source of the pathogen of infection. It is accumulated it in poultry products, such as eggs. Poultry and eggs are dangerous sources of salmonella for people. They can result in the form of severe intestinal disorders and intoxications.

There is hyper-acute, acute, sub-acute, and chronic course of the disease. Affected poultrys appetite deteriorates or disappears. Poultry become sluggish. Eyes are half-closed or closed. Wings are omitted. The main symptom is diarrhea. Diagnosis is based on the analysis of epizootic, clinical, and postmortem data, as well as bacteriological studies. For the treatment of sick poultry, doctors use kolimitsin, eriprim concentrate, and other drugs. The main method of prevention of the disease is observing proper hygiene measures, feeding, and watering of poultry.

Aivian Spirochetosis

Avian spirochetosis is an acute bacterial disease affecting numerous species of birds. It mainly infects turkeys, chickens, ducks, and geese. The causative agent of the disease is Borrelia anserine (Figure 2). It is a spirochete. The main symptoms include anorexia, diarrhea, and leg weakness. It causes paralysis and death. Avian spirochetosis lasts from three to six days (Pattison, McMullin, Bradbury, & Alexander, 2008). It has an extremely high morbidity rate. Penicillin is highly effective in treatment of the disease. The main preventive measure is the hygiene of poultry houses.


Staphylococcus is sporadic or enzootic flowing contagious bacterial disease of all species of birds with clinical signs of acute septicemia, arthritis, and vesicular dermatitis. The causative agent of staphylococcus is spherical shaped micro granules of 0.8-1 microns (Pattison, McMullin, Bradbury, & Alexander, 2008) (Figure 3). They are gram-positive and immobile. Staphylococcus is transmitted from sick poultry in contact, through food, bedding, and water. The incubation period lasts from several hours to several days. Frequent symptoms of staphylococcus include loss of appetite, bowel disorders, and excessive thirst. Diseased poultry die within 10-14 days with a high degree of exhaustion (Speer, 2015). Possible treatments of poultry include terramycin, streptomycin, and penicillin daily for seven days. To prevent staphylococcus, it is necessary to observe the health of animals while harvesting eggs for incubation and day-old chicks, as well as maintain and feed birds according to their age.

Chronic Respiratory Disease

Chronic respiratory disease is a chronic obstructive viral disease that hits the respiratory system of poultry. It is caused by Mycoplasma gallisepticum (Figure 4). A direct contact of susceptible birds with infected poultry is the primary cause of outbreaks. The spread of chronic respiratory disease can also occur via contaminated airborne dust, droplets, or down. Chronic respiratory disease is characterized by respiratory wheezing, cough, runny nose, and sinusitis in turkeys. Besides, appetite is reduced and birds lose weight. In flocks of laying birds, the number of eggs laid is reduced and kept at the reduced level. The infection usually affects all poultry in the flock. However, it varies in severity and duration. The severity and duration of infections increase in the colder months of the year (Pattison, McMullin, Bradbury, & Alexander, 2008). Young birds are affected by chronic respiratory disease more seriously. Mycoplasma gallisepticum can be cured by a number of antibiotics including streptomycin, chlortetracycline, erythromycin, spectinomycin, and others. Since transmission of Mycoplasma gallisepticum is possible through eggs, flocks of poultry free from the infection can only be obtained by growing flocks in strict isolation.


Tuberculosis of poultry is an infectious disease caused by Mycobacterium tuberculosis of an avian type known as Mycobacterium avium (Figure 5). It affects all domestic poultry. The disease occurs in the chronic form. It is characterized by the formation of tubercles specific nodules leading to the collapse of organs and tissues (Speer, 2015). Sick birds in the herd release tuberculosis pathogens into the environment and create favorable conditions for the spread of the disease on the farm. The sources of infection are fecal masses and other secretions of sick poultry. Infection of birds begins in the digestive tract. It is an alimentary infection. Course of the disease, the number of affected organs and tissues, duration and severity all depend on the stability of the birds, the virulence of the pathogen, a mode of infection, and feeding. Currently, there are no effective treatments of tuberculosis in poultry. The immediate destruction poultry suspected to be infected can serve as a preventive measure of tuberculosis.


Aspergillosis is an infectious disease of all kinds of domestic animals caused by fungi of the genus Aspergillus and accompanied by lesions of the respiratory organs and serous membranes. The main agent of aspergillosis of mammals and birds is the fungus Aspergillus fumigatus (Figure 6). Aspergillus species are quite widespread. They live as saprophytes on plant debris and in soil. Feeds affected by fungi are the main source of the pathogen. Aspergillosis can be acute, subacute, and chronic. The incubation period lasts from 3 to 10 days (Speer, 2015). All of them are characterized by such symptoms as fatigue, thirst, the loss of appetite, and muscle tremors. Poultry become inactive and refuse food. Feathers are ruffled. Aspergillosis is difficult to treat. According to the conventional wisdom it is almost impossible to cure. To prevent the spread of aspergillosis in poultry, farmers use iodine preparations such as potassium iodide and sodium iodide with drinking water or food. As preventive measures, poultry should be given only good food.


Coccidiosis is an invasive bird disease caused by single-celled parasitic protozoa coccidia (Figure 7). This disease is different from both viral and bacterial ones as it is caused by celled microorganisms. Chickens, turkeys, ducks, and geese are often infected. In each species of birds, a kind of coccidia peculiar only to them is parasitized. For example, 11 species of coccidia parasitize in chickens (Pattison, McMullin, Bradbury, & Alexander, 2008). Infection with coccidiosis occurs in an alimentary way via feed or water. The latent period of the disease includes 6 to 8 days (Pattison, McMullin, Bradbury, & Alexander, 2008). Typically coccidiosis occurs in the acute form. During weak and repeated infections by different types of coccidian, chronic coccidiosis is possible. The most characteristic symptoms of the disease are oppression, the loss of appetite, rapid and severe emaciation, and frequent defecation until diarrhea. For the treatment of birds, different cytotoxic drugs are used that inhibit the development of the parasite. The complex of preventive measures includes the destruction of oocysts in the environment and isolation of ill birds and their treatment.

Mareks Disease

Mareks disease is a highly contagious viral disease of chickens characterized by paralysis and paresis of limbs, the proliferation of lymphoreticular tissue in the peripheral and central nervous system, eye membranes, internal organs, skeletal muscles, and skin. The causative agent is an oncogenic DNA containing herpes virus of the group B (Figure 8). Chickens, turkeys, pheasants, and guinea fowls are susceptible to disease. The incubation period is from 35 days to 7 months (Hirai, 2012). The initial clinical signs are mild. They include disordered movements. As the disease progresses, lameness intensifies. Paresis and paralysis of organs become obvious. Most frequently, legs, wings, tails, necks, and crops are paralyzed in poultry. Treatment has not been developed yet. The primary method of prevention of the disease is vaccination.

Fowl Pox

Fowl pox is a contagious infectious disease caused by ultra-virus (Figure 9). Infection occurs through a direct contact with sick birds, contaminated objects and feeds, and through bites of infected insects. The virus penetrates the skin and oral mucosa. The incubation period lasts from 4 to 6 days (Chauhan, 2007). Fowl pox is characterized by the appearance of palely yellowish spots. The formation of spots lasts for about seven days and a rash of new spots for about 15 - 20 days (Chauhan, 2007). Then, the process fades. The main symptoms include runny nose and the damage of trachea and lungs. There are no specific ways of treatment. For poultry, it is necessary to create the best possible hygienic conditions.

Newcastle Disease

Newcastle disease of poultry is an acute flowing and rapidly spreading viral disease characterized by lesions of the respiratory system, gastrointestinal tract, and central nervous system, causing massive death of birds. In vaccinated birds with weakened immune systems, the disease can occur without pronounced clinical and pathological features. The causative agent is RNA virus belonging to the paramyxovirus group (Figure 10). In the book Newcastle disease, it is stated that Newcastle disease virus is a very widely distributed virus (Alexander, 2012, p. 201). The incubation period is 3-7 days. In most infected birds, body temperature rises to 44 C. There is lethargy, stiffness, and damage of nervous and respiratory systems. There are no effective drugs for the treatment of Newcastle disease. The main preventive measure is vaccination.


In the environment, there are always many different kinds of viruses and germs that can cause diseases in poultry. All of them have one common feature. They most frequently occur in dirty and unhygienic conditions in henhouses. In such a way, the most effective measures to prevent the occurrence of infectious disease are regular feeding and watering of poultry and hygienic conditions in henhouses.
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