Knowledge, attitudes and practices of Caribbean laboratory workers: adoption of bio-safety guidelines - abstract

Biomedical laboratories are work environments which pose special infectious disease risks to personnel who work in them. With the advent of the AIDS pandemic, emphasis has been placed on adoption of Universal Precautions Policy by all health care workers. In order to assess the extent of safety management, knowledge of, and compliance with established safety standards, laboratory workers in the English-speaking Caribbean were surveyed via an anonymous, self-administered, pre-coded questionnaire. One hundred and thirty-one questionnaires were returned from 16 laboratories in 13 countries (50 percent response rate). Responses indicated that there were universal deficiencies in safety management. Only 38 percent of respondents indicated that a safety manual was readily available. Most staff indicated some familiarity with Universal Precautions but there was inadequate awareness (60 percent affirmative responses) regarding the possibility of contracting infections in the laboratory. There were instances of eating, drinking, smoking, mouth pipetting and recapping of needles. The preliminary survey indicates that there is inadequate compliance with safety standards among laboratory workers in the English-speaking Caribbean. Safety management needs to be improved with intervention strategies designed to heighten laboratory workers' perception of the real risk of infection, in order to accomplish the neccessary behaviour modification. (AU)

Epidemiology of HIV infection and AIDS in Antigua - abstract

In December 1985, the first case of AIDS in Antigua occurred in a homosexual male. As of March 1991, Antigua recorded 43 cases of HIV infection. Seven of these, (16.3 percent) were donors. Apart from one donor, a female, the remaining six donors had unprotected sex with prostitutes. Thirteen (30 percent) of the 43 cases were prostitutes, 10 (1.6 percent) of whom were diagnosed in a serosurvey of 622 prostitutes between January 1988 and March 1991. Despite the heterosexual/prostitute linkage, the male homosexual/bisexual group is significant: 12 (28 percent) of the 43 cases were in this category. There were 13 cases of AIDS with 6 cases (46 percent) in the male homosexual/bisexual group. This figure should be interpreted cautiously since all 13 of the HIV prostitutes returned home to Santo Domingo and the status of 12 of them was unknown. The homosexual/bisexual group does not seem to be closely associated with the heterosexual-prostitute group (AU)

An alternative test strategy for confirmation of HIV serology - abstract

Conventional HIV confirmatory testing algorithms use Western Blot (WB), radioimmunoprecipitation assay (RIPA) or immunofluorescence assay (IFA). All are costly and require well-trained staff. An alternative confirmatory test strategy was evaluated. This involved testing of a panel of 231 stored frozen samples with known WB results with a first generation enzyme linked immunosorbent assay, ELISA (Pharmacia HIV-I E ELISA) and a second generation ELISA (Abbott Recombinant HIV-I ELISA). The panel consisted of 122 WB positive, 37 WB indeterminate and 72 WB negative results. Ninety-six percent of the WB positive samples were positive by both ELISAs; 4 percent gave inconclusive results. Twenty-five (67.6 percent) of the WB indeterminate samples gave inconclusive results by the 2 ELISAs, 11 (29.7 percent) were negative by 2 ELISAs and were probably from truly negative patients. One sample (2.7 percent) was positive by both ELISAs, 53 (74 percent) gave inconclusive results. No WB negative samples gave positive results in both ELISAs. This alternative test strategy could be adopted with results being reported only for samples found clearly positive by both ELISAs (51 percent of samples tested). Other samples should be tested using conventional algorithms. For 51 percent of samples, the cost of confirmatory tests will be reduced from US$70.00 to US$4.00 per samples (AU)

Bacterial-aetiology of neonatal conjunctivitis in Trinidad - abstract

This prospective, consecutive survey of 3,645 babies delivered at the Mount Hope Women's Hospital from March 1 to November 8, 1990 was to determine the aetiology of neonatal conjunctivitis and to compare 3 methods for detection of Chlamydial infection in material from affected eyes. One hundred and twenty babies presented with purulent conjunctivitis within the first four weeks of life and were investigated for bacterial infection including chlamydia trachomatis. Material from infected eyes was examined for the presence of aerobic bacteria by standard bacteriological methods and for chlamydial infection by fluorescein antibody (FA) test, ELISA method and tissue culture. Staphylococcus aureus (40 percent) and Chlamydia trachomatis (11 percent) were the commonest organisms isolated. The prevalence rate of chlamydia trachomatis was 3.84 percent per 1,000 live births. Tissue culture and ELISA methods were more sensitive than the immuno-fluorescence technique. The cost per test for chlamydia trachomatis by the 3 methods varied from a minimum of TT$37.44 to a maximum of TT$63.11. In spite of the cost, it is recommended that testing for Chlamydial as well as bacterial infections should be a routine part of investigating neonatal conjunctivitis (AU)

Yellow fever studies in Trinidad, 1988-1989: attempts to demonstrate Transovarial Transmission of yellow fever virus in Haemagogus mosquitoes collected in nature

Subsequent to an epizootic of yellow fever (YF) in monkeys and the isolation of yellow fever (YF) virus from sylvatic mosquitoes in December, 1988 and January, 1989 in south-east Trinidad, ovitrapping for mosquito eggs was started in January, 1989, in an attempt to demonstrate transovarial transmission of the virus. Multi-paddle ovitraps were used. From a total of 52,632 eggs collected in various parts of the country, the following species of mosquitoes were reared: Haemagogus janthinomys (54 percent), Hg. leucocelaenus (32 percent), Aedes insolitus (12 percent), Hg. equinus (1 percent). When mosquito eggs were removed from the hard board paddles then vacuum-treated for hatching, the process proved very economical in storage space. Most eggs were obtained at the start of the wet season, four to five months after the isolation yellow fever virus from wild caught adult mosquitoes and monkey carcasses. When adult mosquitoes reared from eggs were processed for yellow fever virus, no virus was detected from any of the mosquito pools to indicate that transovarial transmission had occurred (AU)

Sylvatic yellow fever activity in Trinidad 1988-1989

Of a total of 18,068 mosquitoes (361 pools) collected in south-eastern Trinidad forests from December, 1988 to May, 1989, 47 species belonging to 14 genera were identified. Five yellow fever virus isolates were made from Haemagogus janthinomys and one from Sabethes chloropterus. All the other pools of mosquitoes examined were negative for the virus. The mosquito isolates were made in December and January. In addition, in late February and early March, two infected howler monkeys (Alouatta sp.) were detected. Since March, despite continued surveillance, no yellow fever virus has been detected in mosquitoes or monkeys. There has been no reported human infection (AU)

The 1988-1990 epizootic of yellow fever in Trinidad: virological aspects

Sylvatic yellow fever virus activity occurred in Trinidad between December, 1988 and January, 1990. It was first detected in the Trinity Hills area of Guayaguayare in the south eastern forest of the island and subsequently spread west to Moruga and north to Fishing Pond. Surveillance activities in these areas resulted in the collection of over 18,000 mosquitoes and seven monkeys which were referred to the CAREC laboratories for viral investigation. Six pools of mosquitoes yielded yellow fever virus in December, 1988 and January, 1989. Isolations were made from Haemagogus janthinomys (five pools) and Sabethes chloropterus (one pool). Extensive collections in other areas failed to yield virus. Three Alouatta monkeys proved to be infected with yellow fever. These were all Alouatta sp. and were submitted to the laboratory in February and March of 1989 and January of 1990. Thorough virological investigation of febrile persons, with and without liver involvement, showed no evidence to spread to the human population either before or during the epizootic. This was attributed to the high level of immunization achieved in the population following the yellow fever outbreak of 1978-1980 (AU)

Studies on yellow fever in inter-epizootic period in Trinidad

Following an outbreak of yellow fever in Trinidad in 1978-1979, a study was undertaken to investigate the jungle reservoirs and vectors of yellow fever virus in the inter-epizootic period, to seek evidence of natural transovarial transmission of yellow fever virus in Haemagogus collected. These were made four months after the last detection of virus in that area of the island and could not positively be attributed to transovarial transmission. None of the 42,815 progeny of wild mosquitoes yielded virus. No yellow fever virus was isolated from 34,300 mosquitoes other than Haemagogus nor from 15 vertebrates collected in areas of former virus activity. Good progress was made in optimizing the use of the AP-61 cell line resulting in rapid isolation and identification of dengue and yellow fever viruses from Caribbean countries (AU)

Entomological activities during the yellow fever epidemic in Trinidad, 1978-1980

An epidemic of sylvan yellow fever occurred in Trinidad during the period 1978 to 1980. Entomological activities were initiated at various localities where monkey (Alouatta spp.) mortalities were reported. A total of 5,468 Haemagogus janthinomys was collected and tested which resulted in the isolation of 17 strains of yellow fever virus. Two strains of the virus were isolated from a total of 49 Haemagogus leucocelaenus and these constituted the first isolations of yellow fever virus from this species of mosquito from Trinidad. Attempts to demonstrate transovarial transmission of yellow fever virus from adults feared from eggs and larvae collected in the field were unsuccessful. However, from two locations virus isolations were made at the end of rainy season (January) and at the beginning of the successive rainy season (June) (AU)

A clinico-pathological study of yellow fever with demonstration of the virus in the human liver

The clinical histopathological and serological findings in three patients who developed yellow fever after entering the Guayaguayare forest in south-east Trinidad in January and February 1979 are described in this report. The patients were all previously healthy young males and the clinical features of the disease varied from fulminant viral hepatitis with hepato-renal failure to a self-limiting anicteric viral illness. The first patient died, and histopathological examination of the liver was done post-mortem. Needle biopsy of the liver was done on case 2 which presented with the clinical picture of infective hepatitis, and on case 3 with the features of an anicteric viral illness. The histopathological hallmarks of midzonal necrosis, granular eosinophilic degeneration (Councilman bodies) and fatty change in the parenchymal cells of the liver were seen in three cases. The electron microscopic study demonstrated the presence of the yellow fever virus in the liver of the patient who died (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.

A clinico-pathological study of yellow fever with demonstration of the virus in the human liver

The clinical histopathological and serological findings in three patients who developed yellow fever after entering the Guayaguayare forest in south-east Trinidad in January and February 1979 are described in this report. The patients were all previously healthy young males and the clinical features of the disease varied from fulminant viral hepatitis with hepato-renal failure to a self-limiting anicteric viral illness. The first patient died, and histopathological examination of the liver was done post-mortem. Needle biopsy of the liver was done on case 2 which presented with the clinical picture of infective hepatitis, and on case 3 with the features of an anicteric viral illness. The histopathological hallmarks of midzonal necrosis, granular eosinophilic degeneration (Councilman bodies) and fatty change in the parenchymal cells of the liver were seen in three cases. The electron microscopic study demonstrated the presence of the yellow fever virus in the liver of the patient who died.

Entomological activities during the yellow fever epidemic in Trinidad, 1978-1980

An epidemic of sylvan yellow fever occurred in Trinidad during the period 1978 to 1980. Entomological activities were initiated at various localities where monkey (Alouatta spp.) mortalities were reported. A total of 5,468 Haemagogus janthinomys was collected and tested which resulted in the isolation of 17 strains of yellow fever virus. Two strains of the virus were isolated from a total of 49 Haemagogus leucocelaenus and these constituted the first isolations of yellow fever virus from this species of mosquito from Trinidad. Attempts to demonstrate transovarial transmission of yellow fever virus from adults feared from eggs and larvae collected in the field were unsuccessful. However, from two locations virus isolations were made at the end of rainy season (January) and at the beginning of the successive rainy season (June).

Studies on yellow fever in inter-epizootic period in Trinidad

Following an outbreak of yellow fever in Trinidad in 1978-1979, a study was undertaken to investigate the jungle reservoirs and vectors of yellow fever virus in the inter-epizootic period, to seek evidence of natural transovarial transmission of yellow fever virus in Haemagogus collected. These were made four months after the last detection of virus in that area of the island and could not positively be attributed to transovarial transmission. None of the 42,815 progeny of wild mosquitoes yielded virus. No yellow fever virus was isolated from 34,300 mosquitoes other than Haemagogus nor from 15 vertebrates collected in areas of former virus activity. Good progress was made in optimizing the use of the AP-61 cell line resulting in rapid isolation and identification of dengue and yellow fever viruses from Caribbean countries.

The 1988-1990 epizootic of yellow fever in Trinidad: virological aspects

Sylvatic yellow fever virus activity occurred in Trinidad between December, 1988 and January, 1990. It was first detected in the Trinity Hills area of Guayaguayare in the south eastern forest of the island and subsequently spread west to Moruga and north to Fishing Pond. Surveillance activities in these areas resulted in the collection of over 18,000 mosquitoes and seven monkeys which were referred to the CAREC laboratories for viral investigation. Six pools of mosquitoes yielded yellow fever virus in December, 1988 and January, 1989. Isolations were made from Haemagogus janthinomys (five pools) and Sabethes chloropterus (one pool). Extensive collections in other areas failed to yield virus. Three Alouatta monkeys proved to be infected with yellow fever. These were all Alouatta sp. and were submitted to the laboratory in February and March of 1989 and January of 1990. Thorough virological investigation of febrile persons, with and without liver involvement, showed no evidence to spread to the human population either before or during the epizootic. This was attributed to the high level of immunization achieved in the population following the yellow fever outbreak of 1978-1980.

Sylvatic yellow fever activity in Trinidad 1988-1989

Of a total of 18,068 mosquitoes (361 pools) collected in south-eastern Trinidad forests from December, 1988 to May, 1989, 47 species belonging to 14 genera were identified. Five yellow fever virus isolates were made from Haemagogus janthinomys and one from Sabethes chloropterus. All the other pools of mosquitoes examined were negative for the virus. The mosquito isolates were made in December and January. In addition, in late February and early March, two infected howler monkeys (Alouatta sp.) were detected. Since March, despite continued surveillance, no yellow fever virus has been detected in mosquitoes or monkeys. There has been no reported human infection.

Yellow fever studies in Trinidad, 1988-1989: attempts to demonstrate Transovarial Transmission of yellow fever virus in Haemagogus mosquitoes collected in nature

Subsequent to an epizootic of yellow fever (YF) in monkeys and the isolation of yellow fever (YF) virus from sylvatic mosquitoes in December, 1988 and January, 1989 in south-east Trinidad, ovitrapping for mosquito eggs was started in January, 1989, in an attempt to demonstrate transovarial transmission of the virus. Multi-paddle ovitraps were used. From a total of 52,632 eggs collected in various parts of the country, the following species of mosquitoes were reared: Haemagogus janthinomys (54 per cent ), Hg. leucocelaenus (32 per cent ), Aedes insolitus (12 per cent ), Hg. equinus (1 per cent ). When mosquito eggs were removed from the hard board paddles then vacuum-treated for hatching, the process proved very economical in storage space. Most eggs were obtained at the start of the wet season, four to five months after the isolation yellow fever virus from wild caught adult mosquitoes and monkey carcasses. When adult mosquitoes reared from eggs were processed for yellow fever virus, no virus was detected from any of the mosquito pools to indicate that transovarial transmission had occurred.

Surveillance and management of sylvatic yellow fever in Trinidad (1988-1989) - abstract

Howler monkey (Aloutta sp) deaths in the Southeastern forests of Trinidad were reported in December, 1988. This paper reports the laboratory and field investigations and preventive measures which were undertaken, in view of the known association between such deaths and yellow fever (YF) activity. A total of 47,640 adult mosquitoes were captured in several forest regions in Trinidad during the period December 1988 to October, 1989. Mosquitoes were identified, pooled and processed for virus isolation. Blood and organs from 5 dead Howler monkeys submitted between December 1988 and March, 1989 were examined for the presence of YF virus. Virus isolation was done by innoculation of material in AP61 (Ades pseudo-scutellaris) tissue culture and in 2-day-old Swiss albino mice, followed by identification of YF isolates by immunoflourescence, using monoclonal antibody and standard mouse neutralization tests, respectively. Fourty-four species of mosquito belonging to 14 genera were identified. From 654 mosquito pools, 6 YF isolates were obtained from only 2 species: five isolates from haemagogus janthinomys (December, 1988) and 1, for the first time locally, from Sabethes chloropterus (January, 1989). YF virus was isolated from blood and organs of 2 Howler monkeys captured on February 22 and March 2, 1989. There were no human cases of YF. Yellow fever activity appeared to be confined to the southeast part of the island. Preventive measures included mass targeted YF immunization (400,000 doses administered in 3 months), intensified vector control operations and reduced human contact with forest mosquitoes by the existing ban on hunting (AU)

Sylvatic yellow fever activity in Trinidad, 1988-1989

Of a total of 18,068 mosquitoes (361 pools) collected in south-eastern Trinidad forests from December 1988 to May 1989, 47 species belonging to 14 genera were identified. Five yellow fever virus isolates were made from Haemagogus janthinomys and one from Sabethes chloropterus. All the other pools of mosquitoes examined were negative for the virus. The mosquito isolates were made in December and January. In addition, in late February and early March, 2 infected howler monkeys (Alouatta sp.) were detected. Since March, despite continued surveillance, no yellow fever virus has been detected in mosquitoes or monkeys. There has been no reported human imfection. (AU)