Eastern equine encephalitis (EEE) antibody status in St. Thomas, Jamaica, 1975

In 1975, a survey was carried out on 360 persons in the eastern parish of St. Thomas, Jamaica, for antibodies to EEE. Twenty-three of these were found to have positive titres although they showed no clinical symptoms of the disease and gave no past history indicating possible central nervous system infection. While it is possible that nineteen of these persons, over 13 years of age, could have acquired antibodies in the 1962 epidemic, four subjects aged between 8 and 11 years could not. This finding is significant from the public health aspect and warrants further investigation in the possible transmission cycle. This survey was done at a time when there were no reports of an EEE outbreak among humans or equines (AU)

First isolation of a South American strain of eastern equine virus from a case of encephalitis in Trinidad

A South American strain of Eastern Equine virus was isolated from a fatal human case of encephalitis for the first time in Trinidad in 1970. This virus was recovered from the blood and brain of the patient. Validity of the isolate was confirmed by reisolation of the virus from the original materials. The etiological relationship of the virus to patient's illness was established by the demonstration of a secroconversion to the isolate and to the TRVL prototype strain of Eastern Equine virus. A second case of human encephalitis occurred a week later in the same geogrphical area. No virus was isolated but the diagnosis was made on the basis of an immunoconversion. (Summary)

The role of chickens in the epidemiology of eastern equine encephalomyelitis virus in Jamaica

Since 1962, when Jamaica experienced its first and only outbreak of eastern equine encephalomyelitis (EEE), surveillance for the causitive virus has been in progress. Wild birds, rodents, mosquitoes, sandflies and sentinels (domestic chickens, guinea pigs, mice and hamsters) have been constantly examined for EEE virus and serological conversion. In essence, only negative results have been obtained. Since June 1976, domestic chickens have been investigated as a possible reservoir and several have been found to have haemagglutinating antibodies, with titres ranging from 1:10 to 1:160. These titres fell rapidly, eg, from 1:160 to 1:10 within 60 days. These results incriminate the domestic fowl as a major reservoir for the virus, and suggest that the life of immunoglobulins against EEE is short in birds. Thus, the large number of negative serological tests found in previous investigations might be misleading since positive sera might have been missed between intervals of capture and recapture of the birds. The results indicate that investigators could usefully modify their procedure by bleeding wild birds as early as one to two weeks after initial capture. The importance and duration of the dominant avian anti-EEE virus immunoglobins should be investigated (AU).

Equine encephalitis in coastal and hinterland areas of Guyana

Five hundred and eighty-six human sera collected from six coastal and hinterland areas of Guyana, including the principal enzootic foci, have been tested by haemagglutination inhibition against EEE, and WEE antigens. Sixty-eight, (11.6 percent) gave positive results with EEE; one hundred and forty-one (24 percent) against WEE. There was evidence of dual infection in 48 cases (8.2 percent). The highest titer in the case of both EEE and WEE was 1:80 and the lowest 1:10. The results of this serological survey confirm the fact that in Guyana, natural trans of both EEE and WEE arboviruses from equines to Man, has taken place. The vector is as yet unidentified as in the reservoir of virus which must presumably exist during inter-epizootic periods. (AU)

Epidemiological investigations relating to a case of Eastern Equine Encephalitis in a Trinidadian horse

The first equine death in Trinidad known to be due to eastern equine encephalitis (EEE) is reported. Diagnosis was by serologic means only. In related epidemiologic investigations, EEE virus was not isolated from over 5,000 arthropods and the organs of 99 birds, but the serum of five of the birds had neutralizing antibodies to the virus. A strain of Wyeomyia virus and a Turlock-like virus were isolated from the mosquitoes tested (AU)

An outbreak of eastern equine encephalitis on the Courantyne coast of British Guiana

A small outbreak of eastern equine encephalitis involving equines occurred on the Courantyne coast of Berbice County, British Guiana, during July-September, 1962. Attempts to isolate virus from haematophagous insects collected in the epizootic area in October failed. EEE virus was isolated from the brains of two horses. Neutralizing antibodies against EEE virus were demonstrated in serum specimens collected from equines and birds in the area as well as in one of 20 human sera (AU)

An outbreak of eastern equine encephalomyelitis in Jamaica. II. Laboratory diagnosis and pathology of eastern equine encephalomyelitis in Jamaica

Eastern equine encephalomyelitis virus was isolated from man and horses during a outbreak of the disease in Jamaica in November and December 1962. Viruses were isolated from 4 of 7 human brain tissue specimens and from 3 of 6 equine brain specimens. Histopathological evidence of encephalitis was evident in all the tissues examined (Summary)

An outbreak of eastern equine encephalomyelitis in Jamaica, West Indies. 1. Description of human cases

During the outbreak of eastern equine encephalomyelitis (EEE) in Jamaica in November and December 1962, there were 9 deaths among 11 patients clinically diagnosed as having EEE. Five of these cases were confirmed by laboratory tests. Of the two recovered patients, one showed a significant raise in EEE antibody titer and the other showed no demonstratable antibody. The presenting features of illness were mainly fever, headache, neck rigidity, paralysis and drowsiness or coma (Summary)

An outbreak of equine encephalitis in the Rupununi, British Guiana

The virus of eastern equine encephalitis has been shown to be responsible for an epizootic in horses in the Rupununi Savannah, British Guiana. Neutralizing antibodies to both eastern and western equine encephalitis viruses were encountered in equines. Both EEE and WEE were isolated from the brain of a single horse.(AU)