Salmonellosis is the most common and serious zoonosis of the developed world, with some 5 million Americans affected annually.
Although Salmonella spp. are sensitive to many disinfectants as well as cooking, they do survive for extended periods in stagnant water and even longer in soil. Humans typically contract disease by eating incompletely cooked food. Humans may also be infected by exposure to Salmonella spp. shed from poultry or free-living birds, particularly birds roosting at garbage dumps.
Salmonellosis typically presents as gastroenteritis, although any organ can be infected.
Antibiotic therapy is generally contraindicated in man, as this increases the chances of patients becoming carriers.
Campylobacter infection causes acute enteritis and severe abdominal cramps.
The incubation period is 2 to 5 days in humans, and infection is typically self-limiting, lasting 7 to 10 days. Many infected birds become carriers (e.g. 35% of migrating waterfowl and galliformes), although the rate of carrier status is very low in psittacines.
Yersiniosis or pseudotuberculosis is a bacterial infection of birds.
Pigeons and doves are the most common avian reservoir.
Epizootics can occur in birds, leading to major mortalities and massive environmental contamination. Human infections are common in Europe, but only sporadic in the United States.
In humans, incubation is typically 7 to 21 days. The most common form of disease is acute mesenteric lymphadenitis, sometimes with erythema nodosum, an acute, nodular, erythematous eruption usually limited to the lower legs.
Severe enteritis can also occur, with approximately 50% suffering from hepatomegaly and jaundice.
Newcastle disease is an important infectious disease of poultry.
Humans working in close contact with birds such as poultry farmers, slaughterers, and veterinarians can become infected from stock or live vaccine.
The incubation period in humans is 1 to 2 days.
The most common clinical sign is unilateral or bilateral conjunctivitis, although fever, headache, lethargy, pharyngitis, encephalitis and hemolytic anemia can occur.
Illness lasts from 3 days to 3 weeks and recovery is spontaneous.
Allergic alveolitis is a serious, under-recognized condition, which can affect bird owners after exposure to feather antigen. Acute allergic alveolitis occurs 4 to 8 hours after large-scale exposure, resulting in coughing, dyspnea, and fever.
Sub-acute disease occurs after years of moderate exposure and is characterised by a dry cough and progressive dyspnea.
Diagnosis is achieved with intradermal skin testing, and prognosis is good if further exposure to avian antigen can be prevented.
The chronic form results from years of low level exposure to feather dander and is most common in pet bird owners.
Signs include dyspnea, non-productive cough, rales, and weight loss.
Disease is irreversible as the lungs undergo chronic pulmonary fibrosis, but the owner must halt further exposure to prevent further deterioration.
West Nile virus
West Nile virus (WNV) has caused sporadic cases and outbreaks in humans and horses in Europe since the 1960s.
First found in North America in 1999, WNV has spread across much of the the Americas since then.