Ciguatera in Australia. Occurrence, clinical features, pathophysiology and management.

Ciguatera is a type of food poisoning that results from eating certain tropical fish which have become toxic. It is common in Australia: 175 outbreaks, which involved 527 people, were reported in Queensland between 1965 and 1984. It seems restricted to certain areas around the Australian coastline. Most reports have involved the narrow-barred Spanish mackerel, Scomberomorus commersoni, most of which were caught in southern Queensland waters. Up to 2100 cases may have occurred in north Queensland between 1965 and 1984, which were not recorded by the writers. The symptoms of ciguatera in Australia are similar to those reported elsewhere in the South Pacific. Ciguatoxin acts by increasing the permeability of excitable membranes to sodium ions. This type of membrane is found throughout the body in nerve tissue as well as in heart and skeletal muscle. The treatment of ciguatera remains symptomatic and supportive only. Major advances in treatment for ciguatera and detection of ciguatoxin await the means of producing additional ciguatoxin.

Investigation of cholera acquired from the riverine environment in Queensland.

Since February 1977, five patients with cholera apparently acquired the infection from the riverine environment in Queensland. A total of 13 rivers have now yielded at least one isolate of Vibrio cholerae 01 biovar El Tor. Investigations indicate that the organism, including toxigenic strains, can survive and multiply in the riverine environment. No human or animal reservoirs and no ecological niches were identified and no route of importation or dissemination of the organism was discovered. The microbiological examination of faeces in all medical laboratories in Australia should include methods for detecting the cholera organism as a routine. When confronted with a cholera infection, medical practitioners should obtain a history of recent travel, both in Australia and overseas.

The Queensland cholera incident of 1977. 2. The epidemiological investigation.

In 1977 the first case of cholera known to be contracted in Australia during the seventh pandemic occurred in southeastern Queensland. Toxigenic isolates of Vibrio cholerae, biotype eltor, serotype Inaba, phage-type 2, were obtained from the index case, a companion of the patient, the reticulated water supply of their place of residence, and a stretch of the neighbouring river that was being used to supplement fully treated water piped from Brisbane. Treatment of the auxiliary supply consisted solely of chlorination. A section of another river was later shown to contain V. cholerae. No source of pollution was identified for either river. From the persistence of the microorganism in the first river over a two-month period, despite increases in river flow following significant rainfall, it seems that the cholera vibrio can not only survive for a long period but can also grow in the river water. This strongly suggests that certain surface, and possibly subsurface, waters may serve as potential silent foci of V. cholerae. Hence the importance of providing bacteriologically safe water supplies, and the possible need to expand the definition of a 'cholera-receptive area'.

An unusual poxvirus from Nigeria.

A poxvirus of the variola-vaccinia subgroup was isolated from the lesions of a female African refugee suffering from a smallpox-like illness. The virus is interesting because it is neither variola nor vaccinia but combines some properties of each. These properties are described and the possible origin of the virus is discussed.