Monitoring of Alouatta monkeys as an early warning system in yellow fever surveillance

An epizootic of yellow fever occurred in Alouatta monkeys in November 1978. An intensive surveillance programme was initiated to locate sick and dying monkeys in the forests of Trinidad. Thirty Alouatta (red howler)monkeys were collected and examined for yellow fever virus. Sixteen of the monkeys were positive for the virus and these came from south-east, east, and north-west Trinidad (AU)

Laboratory diagnosis of yellow fever infections in humans, alouatta monkeys and haemagogus mosquitoes in Trinidad, 1978-1980

The yellow fever epidemic in Trinidad began with an epizootic in alouatta monkeys in November, 1978. Activity was detected by virus isolation from Alouatta monkeys and from Haemagogus mosquitoes between this date and July 1980. First reports of monkey deaths centered around the Guayaguayare forests of South Trinidad, following which the epizootic spread west to the Moruga area, and north through the Biche Forest reserve, eventually reaching the north-west Chaguaramas peninsula. Surveillance of febrile persons attending clinics and hospitals was intensified and 18 confirmed cases were identified, from 14 of whom yellow fever virus was isolated. In four cases, diagnoses were made on the basis of liver pathology only. Paired sera were obtained from 10 of 11 persons who survived, and in each case serological conversions were obtained by haemagglutination inhibition and mouse neutralization tests. Yellow Fever virus was isolated from 16 of 32 Alouatta monkeys and from 19 of 174 pools of Haemagogus mosquitoes. Two systems were used for virus isolation: the Aedes cell line AP-61 and suckling mice. The former proved to be more sensitive, detecting virus in 11.7 percent of 725 specimens inoculated whereas suckling mice detected virus in 7.9 percent of 724 specimens. In 11 instances virus was detected in an animal or mosquito pool by AP-61 but not initially by mouse inoculation whereas the converse was true in only one case (AU)

Laboratory diagnosis of yellow fever infections in humans, alouatta monkeys and haemagogus mosquitoes in Trinidad, 1978-1980

The yellow fever epidemic in Trinidad began with an epizootic in alouatta monkeys in November, 1978. Activity was detected by virus isolation from Alouatta monkeys and from Haemagogus mosquitoes between this date and July 1980. First reports of monkey deaths centered around the Guayaguayare forests of South Trinidad, following which the epizootic spread west to the Moruga area, and north through the Biche Forest reserve, eventually reaching the north-west Chaguaramas peninsula. Surveillance of febrile persons attending clinics and hospitals was intensified and 18 confirmed cases were identified, from 14 of whom yellow fever virus was isolated. In four cases, diagnoses were made on the basis of liver pathology only. Paired sera were obtained from 10 of 11 persons who survived, and in each case serological conversions were obtained by haemagglutination inhibition and mouse neutralization tests. Yellow Fever virus was isolated from 16 of 32 Alouatta monkeys and from 19 of 174 pools of Haemagogus mosquitoes. Two systems were used for virus isolation: the Aedes cell line AP-61 and suckling mice. The former proved to be more sensitive, detecting virus in 11.7 per cent of 725 specimens inoculated whereas suckling mice detected virus in 7.9 per cent of 724 specimens. In 11 instances virus was detected in an animal or mosquito pool by AP-61 but not initially by mouse inoculation whereas the converse was true in only one case.

Monitoring of Alouatta monkeys as an early warning system in yellow fever surveillance

An epizootic of yellow fever occurred in Alouatta monkeys in November 1978. An intensive surveillance programme was initiated to locate sick and dying monkeys in the forests of Trinidad. Thirty Alouatta (red howler)monkeys were collected and examined for yellow fever virus. Sixteen of the monkeys were positive for the virus and these came from south-east, east, and north-west Trinidad.

Leptospirosis in piggery workers on Trinidad

Of 133 cases of human leptospirosis recorded in Trinidad between 1977 and the end of February 1982, at least eight (6 percent) were in people who worked on pig farms. Three of the eight died,and their presumptive infecting serogroups were Icterohaemorrhagiae (3), Canicola (2), Pyrogenes (2) and Grippotyphosa(1). Six of the eight cases followed up. Altogether, sera from 201 pigs, 78 other livestock animals, 38 workers and 34 dogs were tested for leptospiral agglutinins. The seropositivity prevalence among pigs on farms with human illness(43 percento1:100) was similar to that in pigs from farms not associated with illness (46 percent), but the titres among the former group (geamatic mean 209.5) were higher than among the latter (91.5), where only titers ó1:400 were recorded. Similar infecting serogroups were recorded among pigs on the two groups of farms, with Icterohaemorrhagiae, Autmnalis, Canicola and Pyrogenes most frequently recorded overall. There was little evidence of the pig-adapted serogroups Pomona and Tarassovi. Twelve of 13 workers (93 percent) from a farm on which at least two other people had contracted leptospirosis had serological evidence of exposure, compared with seven of 24 (29 percent) on a neighbouring farm not associated with human illness. Dogs and rodents are thought to be the major sources of leptospirosis in pigs and piggery workers in Trinidad. (AU)

Serological studies on leptospirosis in livestock and chickens from Grenada

Sera from 1206 livestock animals and chickens in Grenada and Trinidad were tested for leptospiral antibodies by the microscopic agglutination test. 376 of the sera were positive (44 percent of those tested in Trinidad and 25 percent of those tested in Grenada). The positive sera were obtained from 25 percent of 324 cattle 35 percent of 130 pigs, 35 percent of 126 sheep, 25 percent of 44 goats, and 11 percent of 175 chickens in Grenada; and 92 percent of 26 cattle, 53 percent of 122 pigs, 76 percent of 86 horses, and 11 percent of 144 chickens in Trinidad. 8 sera from ducks and geese in Trinidad were tested and found to be negative. The serogroups most commonly found to react with sera of the Grenadian animals were Autumnalis, Icterohaemorrhagiae, Hebdomadis and the related serogroups Sejroe and Mini, and Pyrogenes; in the Trinidadian animals they were Icterohaemorrhagiae, Autumnalis, Hebdomadis and its related serogroups and Panama. Strains of serogroup Pomona do not appear to have become established as livestock pathogens on the islands (AU)

A survey of leptospirosis in febrile patients mainly from hospitals and clinics in Trinidad

Acute and convalescent sera were obtained from 202 febrile patients, most of whom were admitted to or attended hospitals or clinics in northern Trinidad during the 12 months from mid-February 1977 to mid February 1978. Laboratory tests confirmed that 10 of the patients were suffering from current leptospirosis while another 54 had serological evidence of previous leptospiral infections. Antibodies to strains of the Icterohaemorrhagic serogroup were the most commonly found, followed by those to the Hebdomadis and Autumnalis serogroups. Isolates were obtained from the blood of two and the urine of three of the current cases. Four of thoses strains were identified as belonging to copenhageni serovar of the Icterohaemorrhagiae serogroup and one to the Bataviae serogroup. Seven of the patients suffering from leptospirosis were male, all rural dwellers, and all except one under 20 years of age. Two of the three female patients were over 60 years old and were urban dwellers. It was not possible to identify the sources of infection with certainty, although dogs may have been responsible for three of the Icterohaemorrhagiae and one of the Canicola infections. Of the 192 patients who were not currently infected, serological evidence of previous infection was obtained in 31 (40 percent) males and 23 (21 percent) females and was most common among farmers and rural workers. (Summary)

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)

The present status of paralytic rabies (Bat-transmitted) in Trinidad

The history of rabies in Trinidad is briefly reviewed. The first cases among cattle appeared in 1925, and in 1929 there were thirteen human deaths. Transmission of the rabies by the fruit-eating bat was demonstrated in 1931. In 1955 a Paralytic Rabies Control Committee was formed. Field work now centres on mass vaccination of cattle rather than on bat destruction. Bat surveys have been made by the Department of Agriculture zoologist, and (7) species other than the vampire bat have been found to be infected with the rabies virus. (AU)

The present status of paralytic rabies (bat transmitted) in Trinidad (abstract only)

The history of bat transmitted rabies in Trinidad is presented and mentioned is made of 89 human deaths, the last occurring in 1937. Deaths in cattle have continued in sporadic fashion but in 1954 the disease again resumed epizootic proportions among livestocks in southern Trinidad. The present programme of control is directed less towards bat destruction and more towards immunization of livestock using a modified live virus avianized vaccine. 24,751 animals, mainly cattle, were thus immunized in 1956. Special studies on bat vectors of rabies are also being conducted. Bat rabies in Trinidad is considered to be a veterinary medical problem posing an ever present threat to public health also. (AU)