[Pathogenesis and pathologic anatomy of human Yersinia infections]

Yersinioses are zoonoses inspite of the fact, that the pathogen is rarely transferred directly from the animal to man, but mostly from contaminated food or contaminated surroundings. Enteritis or enterocolitis develop in most cases after infection with Y. enterocolitica (enteritic form), whereas pseudoappendicitis accompanied by massive mesenterial lymphadenitis of the ileocecal lymph nodes with or without the participation of adjacent parts of the intestine develops after infection with Y. pseudotuberculosis (pseudoappendicitic form). Some complications like arthritis and erythema nodosum occur rather frequently and may help to establish the diagnosis; septicemia occurs very rarely and is as yet lethal in 50% of cases. Confirmation of yersiniosis is in general not possible on clinical grounds only. Also microscopic as well as macroscopic morphological findings will allow a tentative diagnosis only. Confirmation must come from bacteriologic or serologic findings.

An outbreak of Yersinia pseudotuberculosis infection in a small indoor breeding colony of red-bellied (Saguinus labiatus) tamarins

A spontaneous outbreak of yersiniosis caused by Yersinia pseudotuberculosis serotype IIB occurred in a small indoor breeding colony of red-bellied tamarins (Saguinus labiatus) during the winter of 1981. Of 35 monkeys at risk 6 died of an acute or subacute infection over a period of 23 days. Clinical signs were anorexia, weakness, listlessness and depression. The disease was characterized by focal necrosis of the liver, spleen, mesenteric lymph nodes, ulcerative enteritis, and the presence of colonies of Gram-negative bacilli in the lesions. Y. pseudotuberculosis was isolated from the liver, spleen, mesenteric lymph nodes and kidney but not from the blood, lung or intestine. Contaminated food was believed to be the source of infection.

[Use of the keratoconjunctival test for determining the virulence of the causative agent of pseudotuberculosis]

When tested in guinea pigs, Y. pseudotuberculosis strains, serovar I (25 strains) and serovar V (1 strain), were found for the first time to be capable of causing keratoconjunctivitis in the animals; the most virulent of these strains caused progressive conjunctivitis and keratitis with generalized infection. The minimum infective dose was 10(4) for conjunctivitis and 10(6) for keratitis. The studied Y. pseudotuberculosis strains, serovars O3 and O9, were found to be incapable of causing conjunctivitis and keratitis. The authors believe that the keratoconjunctival test allows one to evaluate the invasiveness and toxicity of Y. pseudotuberculosis according to the degree of the manifestation and the time of the development of conjunctivitis and keratitis.

[Yersinioses. Clinical, patho-anatomical and pathogenetic problems (author's transl)]

On the basis of a selected patient group and bioptic material, the difficulties in diagnosing Y. pseudotuberculosis and Y. enterocolitica infections are presented from the clinical and morphological point of view, particularly when extraintestinal complications are present. Taking one patient with Y. enterocolitica infection and recurrent oligoarthritis as an example, the possible pathogenetic significance of circulating immune complexes for the development of extraintestinal symptoms is being discussed.

Fatal Yersinia pseudotuberculosis infection in captive bushbabies

Fatal Yersinia pseudotuberculosis infection was diagnosed in 3 bushbabies (Galago crassicaudatus) in a large prosimian colony. The clinical signs were diarrhea, dyspnea, hyperthermia, dehydration, and lethargy. Histologically, the disease was characterized by lesions of ulcerative enterocolitis, necrotizing hepatitis, splenitis, lymphadenitis, and nonsuppurative pneumonitis.

Yersinia pseudotuberculosis infection in a cat

A diagnosis of Yersinia pseudotuberculosis in a cat was established by microbiological and histological means. Clinical signs were general malaise, anorexia and vomition. Significant laboratory findings included a serum glutamicpyruvic transaminase elevation and the presence of urine bilirubin and urobilinogen. Histological examination of liver biopsies revealed numerous varying-sized foci of caseation necrosis containing large numbers of Gram-negative coccobacilli. Bacteriological techniques, treatment and control measures are discussed.

The histopathology of enteric infection with Yersinia pseudotuberculosis

The gross and microscopic pathologic changes in 70 cases of serologically proven enteric infections with Yersinia pseudotuberculosis are presented. The highest incidence was in young males, and the commonest infecting organism belonged to serologic O-group I. Clinically, the illness resembled acute appendicitis, but the most consistent finding at laparotomy was mesentric lymphadenitis. Surgical specimens examined included 69 mesenteric lymph nodes, 18 appendices, five terminal ileums, and two ascending colons. Histologically, four stages of the disease were identified, leading to the formation of characteristic granulomas with central necrosis and microabscess formation. Ulceration of the intestinal and appendicular mucosa may occur. The illness usually runs a benign course, and antibiotic treatment is rarely necessary. The pathogenesis and differential diagnosis are discussed with reference to the current literature.

Yersiniosis in captive exotic mammals

Within a 2 1/2-month period, Yersinia pseudotuberculosis infection occurred in 3 blesbok (Damaliscus dorcas), 1 dik-dik (Madoqua kirkii), and 1 giant anteater (Myrmecophaga tridactyla) at the National Zoological Park, Washington, DC. Lesions consisted of fibrinonecrotic enteritis and peritonitis, mesenteric lymphadenitis, and embolic pyogranulomatous lesions in the liver, spleen, and lungs. Feed contaminated with the feces of wild rats and pigeons was thought to be the source of infection.

Yersinia pseudotuberculosis in the cat

Yersinia pseudotuberculosis infection in the cat is described. Clinical findings included inappetence, lethargy, rapid emaciation, jaundice and an enlarged left kidney. Chronic pseudotubercular lesions were found in the kidneys and lungs and Yersinia pseudotuberculosis Type IIB was recovered from both sites.

Pseudotuberculosis (Yersinia enterocolitica) in the owl monkey (Aotus trivirgatus)

Pseudotuberculosis caused by Yersinia enterocolitica was observed as an enzootic disease of the owl monkey (Aotus trivirgatus). A description is given of the natural disease and its successful reproduction in owl monkeys. The disease was characterized by purulent and necrotizing enteritis, hepatitis, and splenitis. Large colonies of the causative organism were consistently associated with the lesions. Although pseudotuberculosis has been reported in other monkeys, the disease in the authors' primate colonies has been restricted to the owl monkey.

Clinical and laboratory aspects of Yersinia pseudotuberculosis infections, with a report of two cases

Yersinia pseudotuberculosis infections in two bacteriologically confirmed cases are described. A child was found to have mesenteric adenitis and an adult had septicemia. Invariably simulating acute appendicitis, mesenteric adenitis most often occurs in male children and adolescents. Septicemia with this organism usually affects elderly, debilitated patients, who frequently have chronic hepatic disease. The infrequent diagnosis of infection with Yersinia pseudotuberculosis in the United States is probably due to failure to consider it a human pathogen. Currently classified with the Enterobacteriaceae, Yersinia pseudotuberculosis in a non-lactose-fermenting, Gram-negative coccobacillus. It is sensitive to a wide range of antibiotics, including tetracycline and streptomycin, but usually is resistant to ampicillin. Yersinia pseudotuberculosis has a worldwide distribution in wild and domestic mammals and birds. Infections in man may result from direct contact with infected animals or their excreta.