A behaviour study on the potential for direct transmission of tuberculosis from possums (Trichosura vulpecula) to alpacas (Lama pacos), and the converse from alpacas to possums

Aims. To evaluate the potential for the direct transmission of tuberculosis from possums to alpacas, and vice versa.

Methods. A field study was conducted on an alpaca farm in Northland, New Zealand on 7 January 1999. Observations were recorded on the interaction of one group of male alpacas with a simulated dead possum, one male and one female alpaca group with a simulated terminally tuberculous possum, and one group of male alpacas with a normal possum in an enclosure from which the animals could not escape. The possum was sedated with ketamine as hydrochloride to simulate death (inactive; no movement), and terminal illness (active, into-ordinated movement around the paddock). The observations were based on the focal animal sampling technique, they were un-replicated, and recorded visually and manually with intermittent still photography.

Results. Both male and female alpacas showed strongly inquisitive interaction with the possum. They clustered around the possum (focal animal) very soon after it was observed by the first member of the group. The interest of the majority of both sex groups remained high for the observation periods of approximately 30 minutes, and most individuals remained within 5 metres of the possum for that time. Approximately 50% of the alpacas were within possible aerosol transmission distance of 2 metres from the sedated, erratically mobile possum with their heads towards it for approximately 50% of the two observation periods. Aggressive behaviour was recorded for a young male with stamping on the moving possum. Similar, but more vigorous and prolonged stamping behaviour was recorded for a female with a young (<1 week) offspring (cria).The stamping behaviour was accompanied by very close nose to nose contact of the alpaca and possum. At one point the female threw the possum approximately 1.5 metres in the air with her teeth. The group of male alpacas placed in an enclosure with an unsedated normal possum generally moved away from the possum during its rapid active attempts to escape. When it became inactive their approaches were cautious and only once elicited a defence reaction from the possum, from which they recoiled. One male made one attempt to stamp on the active possum. Soon after the possum became inactive in a small loose hay pile, the alpacas lost interest in it.

Conclusions. The alpaca / possum behavioural interactions show there is potential for direct aerosol transmission of tuberculosis from possums to alpacas, but probably not from alpacas to possums.     

The economic impact of AIDS in the United States

This analysis of several previous studies of the cost of AIDS suggests that the lifetime cost of medical care per patient will not exceed +80,000, an amount similar to the cost of treating other serious illnesses. If current projections of future AIDS cases are accurate, the cumulative lifetime costs of 270,000 cases diagnosed between 1981 and the end of 1991 will not exceed +22 billion. This amount is small compared with total U.S. medical spending. The economic impact of AIDS on San Francisco, New York, and some other cities, however, is likely to be more serious. The AIDS epidemic will also highlight the financial problems of Americans who face large medical bills without adequate insurance.     

Eosinophilic myeloproliferative disorder in a horse

An eosinophilic myeloproliferative disorder resulted in edema and hemorrhagic diathesis in a 10-month-old Standardbred colt. Laboratory abnormalities included severe thrombocytopenia, anemia, mild hypoproteinemia, and marked eosinophilia. Circulating eosinophils were immature or atypical with variation in granule size, disproportionate nuclear to cytoplasmic maturation, and abnormal nuclear size and shape. Bone marrow aspirate had mainly atypical eosinophil precursors, few erythroid precursors, and no megakaryocytes. A blood transfusion and dexamethasone therapy resulted in some improvement; however, the horse was euthanatized due to poor prognosis. Postmortem examination showed gastrointestinal parasitism; histologically the spleen was infiltrated by atypical eosinophils and there were sites of eosinophilopoiesis. The disease was broadly similar to idiopathic hypereosinophilic syndrome in people, but typical cardiac and neurologic involvement of hypereosinophilic syndrome were absent. Progressive myelophthesis and marked eosinophil atypia suggested malignancy.     

FC-9 Coat funk in Alaskan malamutes

The purpose of this study was to describe a new hereditary sensory neuropathy in French spaniels resulting in analgesia and progressive mutilation of the distal extremities. Thirteen French spaniels (six females, seven males) from five different litters with acral mutilation were identified. Clinical signs were first noted between 3.5 and 12 months of age and typically consisted of sudden excessive and intense licking and biting of toes and/or footpads of one or several feet. This generally progressed rapidly into swollen digits, paronychia, footpad ulceration, and occasionally fracture and osteomyelitis. If the affected dogs were unrestrained, auto-amputation of claws, toes and footpads usually resulted. However, even in the more severe cases, affected dogs walked and ran on their mutilated feet without any evidence of lameness, pain or ataxia, and they allowed wound care without evidence of pain or discomfort. Dogs were otherwise healthy, with the exception of frequent secondary bacterial infections of the wounded feet. This disorder was clinically very difficult to manage, and the majority of the dogs were euthanized within days to months of diagnosis. None of the sires or dams of the affected dogs reported here were clinically affected. There was no apparent sex predilection. An autosomal recessive mode of inheritance was strongly suspected. The clinicopathological findings, the early age of onset and the disease progression in affected French spaniels were very similar to those reported for hereditary sensory neuropathy in German short-haired pointers, English pointers and English springer spaniels.
Funding: Self-funded.