An outbreak of toxoplasmosis in zoo birds

CLINICOPATHOLOGICAL FEATURES OF TOXOPLASMOSIS IN FOUR RED PANDAS (AILURUS FULGENS)

Two geriatric red pandas (Ailurus fulgens) over a 4-yr period presented with vague clinical signs including anorexia, lethargy, and difficulty ambulating. Treatment protocols using enrofloxacin, steroids, and clindamycin were unsuccessful. Necropsy examination confirmed disseminated toxoplasmosis infection in these cases, and a modified agglutination test had been positive for a prolonged period of time before one panda showed signs of disease. A review of the Red Panda Species Survival Plan pathology database revealed two additional cases of disseminated toxoplasmosis in geriatric red pandas. Many organ systems were affected, but dissemination to the brain, lungs, and liver predominated. Immunohistochemistry or polymerase chain reaction was required to confirm a diagnosis in serologically positive animals, as well as in animals in which a histological diagnosis was suspected. This case series describes the clinical and pathological features of toxoplasmosis in geriatric red pandas.

A review of toxoplasmosis in wild birds

Toxoplasma gondii affects most species of warm-blooded animals, including birds. There is considerable confusion regarding the identity of T. gondii-like parasites and the diagnosis of toxoplasmosis in wild birds. In this review, T. gondii-like infections in different species of wild birds are reviewed with particular reference to prevalences, clinical signs, pathology, diagnosis, and treatment. Although subclinical T. gondii infections are prevalent in many avian species, toxoplasmosis can be clinically severe in pigeons and canaries. Blindness associated with T. gondii in canaries is reviewed in detail.

Experimental toxoplasmosis in budgerigars (Melopsittacus undulatus)

The susceptibility of budgerigars (Melopsittacus undulatus) to graded doses of Toxoplasma gondii oocysts was studied. Sixteen budgerigars were divided into 4 groups (A-D) of 4 each. Birds in groups A-C were fed 100,000, 1,000, or 100 infective oocysts of the VEG strain of T. gondii, respectively. Budgerigars in group D were not fed oocysts and served as controls. All 4 birds in group A died (or were killed) because of acute severe enteritis 5 or 6 days after feeding oocysts (DAFO). Three of the 4 birds in group B were killed (or died) because of toxoplasmosis 9 or 14 DAFO. One budgerigar in group C and the 4 budgerigars in group D remained healthy and were killed 35 or 39 DAFO. Toxoplasma gondii was demonstrated in tissues of all budgerigars fed oocysts. The control budgerigars remained clinically normal and showed no evidence of T. gondii exposure. These results indicate that, compared to other passerines, budgerigars are relatively resistant to clinical toxoplasmosis.

Wild animals as reservoirs of infectious diseases in the UK

This review aims to illustrate the extent to which wildlife act as reservoirs of infectious agents that cause disease in domestic stock, pet and captive animals and humans. More than 40 agents are described. In the case of some of these, e.g. Cryptosporidium spp., Escherichia coli O157 and malignant catarrhal fever, the current evidence is that wildlife either does not act as a reservoir or is of limited importance. However, in the case of many important diseases, including bovine tuberculosis, Weil's disease, Lyme disease, avian influenza, duck virus enteritis and louping ill, wild animals are considered to be the principal source of infection. Wildlife may be involved in the epidemiology of other major diseases, such as neosporosis, Johne's disease, mucosal disease and foot and mouth disease, but further studies are needed. The UK would benefit from a more positive approach to the study of wildlife and the infections they harbour.

High Toxoplasma seroprevalence associated with meat eating habits of locals in Nepal

A serosurvey of Toxoplasma gondii infection in apparently healthy subjects (n = 404) living in Achham (n = 215) and Dang (n = 189) districts in western Nepal was carried out. An interview with 249 participants, each representing a household, was also conducted. This interview pertained to their meat eating habits and the keeping of cats in their houses. Toxoplasma antibodies were detected by using the microlatex agglutination test. The overall seroprevalence was 65.3% with no significant difference in the two districts (Achham: 66.9% and Dang: 63.5%) included (p = 0.546). Females and the Indo-Aryan ethnic-group showed marginally higher prevalence compared with their male (p = 0.545) and Tibeto-Burman (p = 0.075) counterparts. The majority of the infections was found to have occurred during childhood. The frequency of meat eating in western and eastern regions differed greatly (p = 0.000) with the people in the eastern region being frequent meat eaters than those in the western region. About one-third of the subjects, all Indo-Aryans, in the western region had the raw meat eating habit but none in the eastern region. Approximately 7.0% of households in both western and eastern regions kept cats. The present findings demonstrated a typical role of meat eating habits of people in the high Toxoplasma seroprevalence in Nepal.

Disseminated toxoplasmosis in magpie geese (Anseranas semipalmata) with large numbers of tissue cysts in livers

Fatal disseminated Toxoplasma gondii infection was diagnosed in 2 captive magpie geese (Anseranas semipalmata) from a zoo in Texas. Both geese died suddenly, without apparent clinical signs. Lesions associated with T. gondii tachyzoites were seen in lungs, pancreas, liver, adrenals, bursa of Fabricius, spleen, brain, and kidneys. Toxoplasmic pneumonia and hepatitis were considered to be the primary cause of death. An unusual feature was the presence of numerous tissue cysts in hepatocytes of both geese. The diagnosis was confirmed immunohistochemically. Antibodies to T. gondii were found in 2 of 11 other geese from the zoo examined using the modified agglutination test. This is the first report of T. gondii infection in magpie geese (Anseranas semipalmata).

Experimental toxoplasmosis in Japanese quail

Twenty-four 5-month-old battery-hatched Japanese quail were inoculated orally with 10(5) (ME 49 strain, group A, 6 birds), 10(3) (ME 49 strain, group B, 6 birds), 10(5) (GT-1 strain, group C, 6 birds), and 10(3) (GT-1 strain, group D, 6 birds) Toxoplasma gondii oocysts. All birds in group C died or were euthanized within 8 days after inoculation (DAI). Five of the 6 birds in group D died or were euthanized 8, 9, 15, 19, and 23 DAI. One of the 6 quail in group A died 9 DAI, and 1 of the 6 birds in group D died 16 DAI. The 11 quail (1 from group D and 10 from groups A and B) were euthanized 63 DAI; T. gondii was isolated by bioassays in mice from the brains of 10, hearts of 10, and skeletal muscles of all 11 quail. Quail that survived marked small intestinal and splenic toxoplasmosis lived long enough to develop severe protozoal pneumonia, myocarditis, or meningoencephalitis. The quail that survived only to be examined at 63 DAI had moderate multifocal nonpurulent encephalitis and myositis and had a hypertrophic spleen that contained hemosiderin-laden macrophages. Toxoplasma gondii antibodies were found in the sera of all quail examined 63 DAI. Antibody titers to T. gondii in the modified agglutination test were higher than in the indirect hemagglutination and latex agglutination tests. Antibodies were not detected in quail sera examined by the Sabin-Feldman dye test.

Incidence of Toxoplasma infection in a population of European starlings Sturnus vulgaris from central England

A sample of European starlings, Sturnus vulgaris, culled from a communal roost in a city in Central England, was examined for infection with Toxoplasma. Eleven (8%) of 133 birds were confirmed as infected after horizontal passage of brain homogenate through mice. Serological examination, using the indirect and direct agglutination tests, proved unsatisfactory for screening starlings for Toxoplasma infection. If the proportion of starlings infected with Toxoplasma in this sample is representative of the population as a whole, then this bird could play an important role in the maintenance of the infection in urban environments.