Comparison of HHV-6 antibody titers in West Africa and the Caribbean

Human herpesvirus-6 (HHV-6) infections seems to be ubiquitous early in life, but antibody responses vary by geographic area. We compared HHV-6 antibody titer in 123 West African and 122 Caribbean serum samples. A quantitative immunofluorescence assay (IFA) using antigens derived from an HSB-2 cell line was used to test for IgG HHV-6 (GS strain) antibodies. The prevalence of HHV-6 antibodies was high (98 percent) in both sites. African samples had a significantly higher geometric mean titer (GMT: 697) than did Caribbean samples (GMT: 99). There was no difference between males (GMT: 260) and females (GMT: 270) overall. Children up to and including 9 years old had significantly higher titers (GMT: 483) than did all others (GMT: 237), and female children tended to have higher titers than did male children. In both areas there was a trend towards highest titer at younger age, followed by a decrease in titer in the oldest age group. Environmental and host factors may explain these geographic differences in antibody responses between two groups of African origin. (AU)

Seroprevalence of autoantibodies in selected and unselected populations in Jamaica

Various serological techniques were used to investigate the prevalence and distribution of autoantibodies in healthy Jamaicans and patients with autoimmune and non-autoimmune disease. Low concentrations of autoantibodies were found in healthy Jamaicans, including thyroid (1.5 percent), gastric parietal cell (1.4 percent) and smooth muscle (11.3 percent). There was no significant age or sex predominance in the distribution of autoantibodies in the healthy population though autoimmune disease was more prevalent in females. Serological overlaps occurred but the comparative distributions and concentrations of autoantibodies in patients with autoimmune disease and non-autoimmune disease, and health subjects indicate that currently available methods of autoantibody determination may be used successfully in diagnosis in Jamaica. Failure to detect circulating pancreatic islet cell antibodies in insulin-dependent diabetic patients as well as in healthy Jamaicans questions the pathogenicity of these antibodies and diminished their diagnostic usefulness in this population. (AU)

Serological tests for lyme disease in patients with tropical spastic paraparesis and healthy Jamaicans

The significance of reactive serlogical tests for lyme disease in patients with tropical spastic paraparesis (TSP) was assessed by examining serum samples from 128 of these patients and 200 healthy Jamaicans by lyme indirect immunofluorescent antibody (IFA), enzyme immuno-assay (EIA) and western blot analyses. Sera were also examined in serological tests for syphilis (STS), an unabsorbed fluorescent treponemal antibody test and leptospira microagglutination test. The prevalence of positive Lyme IFA and EIA results did not differ significantly between sera from TSP patients (12.5 percent and healthy controls (10.0 percent). Western blot analyses showed that the positive lyme IFA and EIA results observed in this study were due to false positive reactions. Seventy-five per cent of lyme IFA/EIS positive sera from TSP patients had treponemal antibodies. Eighty per cent of those from healthy controls were negative in standard STS but 85 percent were positive when tested in an unabsorbed fluorescent treponemal antibody (FTA). These data indicate that reactive serological tests for lyme disease in Jamaican TSP patients and healthy Jamaicans are false positive reactions due to cross-reactivity with other spirochaetes, notably treponema pallidum and non pathogenic treponemes (AU)

Evaluation of methods for the laboratory diagnosis of malaria in Guyana

When 297 blood samples taken from patients attending a fever clinic in Georgetowm Public Hospital were examined microscopically, after thick and thin blood films had been stained with Giemsa, one hundred and forty-two (47.8 percent) were microscopically positive for malaria. After processing the patients' serum samples by the Indirect Fluourescent Antibody (IFA) technique, specific IgG and IgM antibodies were detected in 239 (81.3 percent) and 179 (60.1 percent), respectively, of the sera. Based on the microscopical findings, the IFAT gave positive and negative values of 54.4 percent and 81.8 percent (IgG), and 57.5 percent and 67.8 percent (IgM), suggesting that the IgM would be more useful than the IgG in the diagnosis of current malaria. An odds ratio analysis showed that the presence of symptoms, IgG or IgM antibodies, as well as visits to endemic regions, could be good indicators of current malaria. Age and occupation are not. The microscopical method will continue to be the gold standard - the best available criterion for the validation of our tests - for our diagnosis of acute malaria. (AU)

Chlamydial infections in selected populations in Jamaica

The importance of Chlamydia trachomatis as a cause of genital tract infection in Caribbean countries is largely unknown. Two hundred and sixteen cervical and urethral specimens were collected from patients with cervicitis and urethritis attending a Sexually Transmitted Diseases (STD) Clinic, a Gynaecology Clinic and a Family Planing Clinic in Kingston. Specimens were tested for chlamydiae by direct immunofluorescence and cell culture methods. They were also investigated for N. gonorrhoeae infections. Seventy-two of 138 patients (52.2 percent) at the STD Clinic were positive for chlamydiae; 28 of 50 ((56.0 percent ) from the Gynaecology Clinic and 11 of 28 (39.3 percent) from the Family Planning Clinic were positive. The prevalence of C. trachomatis (52.3 percent) was higher than that of N. gonorrhoeae (11.1 percent) in all groups. The results indicate that C. trachomatis is a common cause of genital tract infections in Jamaica(AU)

The comparative value of various diagnostic tests for malaria - abstract

When 300 blood samples taken from patients attending a fever clinic in Georgetown Public Hospital were examined microscopically, 47.6 percentwere found positive for malaria. IgG antibodies stored in filter paper or liquid serum gave 68 percent and 81 percent positive rate, repsectively. Sixty-one per cent (61 percent) of the patients had positive levels of IgG antibodies. Elevation of the cut-off point of IgG antibody titres from 1:256 to 1:1,024 help to reduced false positives of the indirect flourescent antibody test. Clinical symptoms, visits to endemic areas, occupation and its life styles, as well as age could assist in making a diagnosis. The microscopic method will continue to be the gold standard (AU)

Comparison of a human T-cell lymphotropic virus type I strain from cerebrospinal fluid of a Jamaican patient with tropical spastic paraparesis with a prototype human T-cell lymphotropic virus type I

The isolation and characterization of a human T-cell lymphotrophic virus type I (HTLV-I) from cerebrospinal fluid of a Jamaican patient with tropical spastic paraparesis is described. The virus isolate is a typical type C retrovirus as seen by electron microscopy and is related to prototype HTLV-I isolated from patients with adult T-cell leukemia but is not identical to this prototype HTLV-I as seen by restriction enzyme mapping.(AU)

Identification of an antigenic and genetic variant of dengue-4 virus from the Caribbean

Twenty-one dengue (DEN) viruses isolated from the Caribbean (Dominica and Jamaica) during the 1981-1982 epidemic year were distinct serological and genetic variants of DEN-4 virus. These isolates were clearly identified as DEN-4 viruses using type-specific monoclonal antibodies in indirect immunofluorescence assays. However, they either were not neutralized, or were neutralized poorly using hyperimmune mouse ascitic fluids (HMAF) or rhesus monkey serum directed against the H-241 prototype strain of DEN-4 virus isolated in the Philippines in 1956. HMAF prepared against a representative Caribbean isolate, however, neutralized with similar effectiveness the homologoous virus, the H-241 prototype strain, and virus strains isolated from the Pacific and Southeast Asian areas from 1973 to 1984. The Caribbean isolate exhibited no more than 30 percent and 16 percent oligonucleotide spot homology with the H-241 and Bankok viruses, respectively, by RNA fingerprint analysis, while demonstrating 82 percent and 89 percent homology with the Gilbert and Niue Island isolates, respectively. The isolation of dengue viruses which are serologically and genetically distinct from the prototype virus emphasizes the need for continued dengue virus surveillance. The recognition of unique dengue isolates should allow the selection of reference strains and vaccine candidate strains which will induce antibodies that are equally effective in neutralizing virus from all geographic areas. (AU)

Evaluation of an immunofluorescence test for the diagnosis of gonorrhoea

Sera from 336 Jamaicans were tested, using a mixture of local strains of N. gonorrhoeae as antigen in an indirect flourescent antibody test. (IFA) At 1:6 serum dilution, the sensitivity of test was high (100 percent in females with culture-proven gonorrhoea). Geometric mean titres in culture-negative females witha history of gonorrhoea contact were significantly higher than in females with non-gonococcal vaginitis (81 and 47 respectivity). There was no significant difference between the GMT of males with current uncomplicated gonorrhoea and controls (43 and 37 respectively). Absorption studies showed that N. gonorrhoeae-specific antibodies were present in 25 percent of culture-negative, 67 percent culture-positive patients and 20 percent of blood donors. The specificity of the test was markedly improved at 1:128 serum dilutions, when the predictive value of a positive result was 95 percent. We consider this IFA test to be a useful adjunct to the diagnosis of gonorrhoea. (AU)

A study of enteric parasites in three closed communities in Trinidad and Tobago

A study to determine the current status of enteric parasitic infections in children in three institutions of Trinidad and Tobago was initiated in 1977. The three institutions, represented distinct populations, namely the mentally retarded, the physically handicapped and the socio-economically deprived. A total of 450 children was involved in this study, which provided both qualitative and quantitative data. Faecal samples were collected from each participant, from which fifty (50) milligram portions were subjected to the formal-ether concentration technique and examined for ova, cysts and larvae, and these quantified. Cultures were also set up as a diagnostic aid and with regard to helminth larvae present in the faecal concentrates. The highest prevalence rate of intestinal parasites was found at the institution for the mentally retarded, and this was in agreement with data obtained by other workers throughout the world. The data showed that intestinal parasitism is common in this particular group, both in children and adult populations. Next in order of prevalence was the residents of the orphanage (48 percent) and then the physically handicapped group (23 percent). The intensity of infection was also highest in the mental retardates, which reflected on the ingestion of large numbers of embryonated ova and viable cysts. The drug mebendazole, a broad spectrum anthelmintic was used to treat the various helminth infections, the most prevalent being that caused by Trichuris trichiura, the intensity of those infections being monitored before and after mebendazole treatment. The pattern which emerged was that one month after drug therapy, most faecal samples were either completely negative or ova counts were extremely low. Four to six months after administration of the drug however, the ova counts had reverted to or exceeded their former levels, thus indicating that transmission had taken place. A change in the physical environment at this institution, appeared to have modified this situation by the elimination of embryonation sites, with a subsequent reduction in the intensity of infection. Unlike the mental retardates, the intensity of infection at the other two institutions was low, except for one heavy hookworm infection at the orphanage. These low intensity infections may be an indication of a low level of envionmental pollution, coupled with a higher level of personal hygeine and sanitation in these two populations. The helminths found in this study were Ascaris lumbricoides, Trichuris trichiura, Strongyloides stercoralis and Hookworm, the prevalence of these organisms varying from institution to institution. Amongst the protozoa the following organisms were found, Entamoeba coli, Entamoeba histolytica, Entamoeba hartmanni, Endolimaz nana and Iodamoeba buetschlii, representing the amoebae, whilst the only flagellate found was Giardia intestinalis. The intensity of these infections varied throughout the institutions, being highest at St. Ann's Hospital, where ova counts of 3 000 ova/50mgm of faecal sample were frequently encountered. With regard to the protozoal cysts these were graded on the number of cysts per high power field as being heavy, moderate, light and rare. Many heavy Giardia intestinalis, Entamoeba coli, Endolimax nana and Iodamoeba buetschlii infections were met. This study is of relevance in that it highlights areas often neglected by the medical authorities, attention being focussed in these areas only when some precipitating factor, such as the outbreak of diarrhoea occurs. Recommendations were made which at best could bring about total eradication or else reduce prevalence rates and intensity of infection to tolerable levels, that is to levels comparable to that of the community at large (AU)

Serological and clinical evidence of toxoplasmosis in the Upper Leeward Islands

Toxoplasma infections are common on the Upper Leeward Islands (Saba, St. Maarten and St. Eustatius, Neth. Antilles) as proved by clinical evidence and serological determinants in patients and in healthy people. In schoolchildren an overall positive percentage of 45.5 percent was found. On St. Eustatius the highest frequency of recent infections was in the youngest age groups, in contrast with findings in the Netherlands and in Germany (AU)

Immunologic diagnosis of schistosomiasis. III. The effects of nutritional status and infection intensity on intradermal test results in St. Lucian children

The question of the insensitivity of immediate and delayed skin testing in children was studied with respect to both nutritional status and intensity of infection. Ninety-seven children on the island of St. Lucia, 5 to 11 years of age, with almost equal male:female distribution, all excreting eggs of Schistosoma mansoni were tested as follows: qualitatively and quantitative stool examinations; anthropometric measurements (height, weight, mid-arm circumference and triceps skinfold thickness); hematocrit; fluorescent antibody test; and skin tests with control material, S. mansoni adult worm antigen (both Puerto Rican and St. Lucian strains), and intermediate strenght PPD tuberculin. The anthropometric measurements revealed marginal malnutrition among the children. The overall positive intradermal response rate for each of the two antigens was similar, being 56 percent for the immediate and 37 percent for the delayed test. There was no relationship discernible between relative over- and under-nutrition and the skin test responses. A striking and highly significant positive association was revealed, however, between the intensity of infection, as shown by quantitative egg counts, and the sensitivity and extent of both the immediate and delayed skin test reactions.(AU)

Immunologic diagnosis of Schistosomiasis. I. A controlled study of intradermal (immediate and delayed) and serological tests in St. Lucians with Schistosoma mansoni and in uninfected St. Vincentians

In order to test the efficacy of antibody-mediated immunologic methods for the diagnosis of schistosomiasis (immediate intradermal and serological tests) and to compare them with a cell-mediated immunologic reaction (the delayed intradermal test), 350 subjects were examined. Approximately half of them were from the West Indian island of St. Lucia, all with proven schistosomiasis mansoni on fecal examination, and the other half were comparable subjects from St. Vincent, an island 30 miles distant where schistosomiasis has never been found. Five different antigens utilized in the intradermal tests (prepared from Schistosoma mansoni cercariae, adult worms and eggs, and from S. haematobium and S. japonicum eggs) were injected blindly in a randomized manner. The antigens were almost equally and highly sensitive in the immediate skin reaction in the adult St. Lucians (89-95 percent, with the exception of S. haematobium, 74 percent), but were far less sensitive in the children. There was a large number of false positive immediate responses among the Vincentians, e.g., 44 of 171 subjects tested with the S. mansoni cercarial antigen. Delayed skin reactions, which among the St. Lucians reached a peak of 66 percent positively with S. mansoni adult worm antigen, were less sensitive than the immediate reactions, but appeared to be more specific. Among the antigens (S. haematobium and S. japonicum eggs), while the Vincentians had very few false positive reactions with the homologous and none with the heterologous antigens. Of the three serologic tests (complement fixation, cholesterol-lecithin flocculation, and flourescent antibody), the first two were insensitive and non-specific; the third was the only one that provided results which were at all acceptable.(AU)

The prevalence of salmonellae in poultry, cattle, pigs and animal feeds in Jamaica

The prevalence of Salmonella in certain food animals - poultry, cattle and pigs - and their food stuffs, was investigated in Jamaica for the first time. A total of 1,076 samples were examined. Samples of faeces and cloacal swabs were taken from poultry at the time of slaughter, at a processing plant in Jamaica in 1968. This was repeated in 1971 when poultry from three other plants were also tested. 28 of 323 (8.7 percent) samples yielded Salmonella. The recovery rate for the factories varied between 0 percent and 15 percent. The patterns of recovery indicated that good sanitation and equipment lowered the incidence of salmonellae in poultry. Serotypes isolated were S. blockely (8 isolates), S. typhimurium var copenhagen and S. albany (6 isolates each), S.bredeney (5 isolates), S. saint paul, S. infantis and S. haadt (one isolate each). Improved methods of sanitation appear to be needed, especially for handling giblets. A survey of pigs and cattle at the Kingston abattoir was made in 1968 and repeated in 1972. At the first survey 52 samples were taken from cattle and consisted of swabs of liver, spleen and mesenteric lymph nodes. 25 samples were taken from pigs, consisting of swabs of liver and spleen. No salmonellae were recovered. During the second survey in 1972, a total of 101 samples were taken from pigs, cattle, the environment (cutting surfaces, knives, floors, etc.) and from the abattoir effluent. Thirty six percent of these were found to be positive for Salmonella. Mesenteric nodes (comminuted) and faecal swabs together yielded 3 Salmonella isolates from 24 samples of cattle (12.5 percent) and 24 Salmonella isolates were made from 41 samples of pigs (54 percent). The differences in recovery of salmonellae between the two surveys was considered to be due to differences in sampling method and site. The efficiency of recovery of Salmonella from these two sources was compared. Brilliant Green (BG) and xylose-lysine-deoxycholate (XLD) agars, were compared for relative rates of recovery of salmonellae. The serotypes isolated from cattle were S. ohio (2 isolates) and S. meleagridis (one isolate). Ten of the 22 isolates cultured from pigs were serotyped with the following results: S. anatum (3 isolates), S. senftenberg (2 isolates), S. derby (2 isolates), S. heidelberg (one isolate), S.bonariensis and S. meleagridis (one isolate each). One hundred and thirteen samples of animal feeds and feed ingredients were analysed for Salmonella in 1968. Seven (6 percent) of these were found to be positive by the conventional cultural (CC) method. Fifty eight of these were also examined by the fluorescent antibody (FA) method of Ellis, and 9 were found positive for Salmonella. However, only 4 of these were confirmed by the CC method. Three that yielded Salmonella by the CC method were negative by FA. Serotypes isolated were S. eimsbuettel (4 isolates), S. senftenberg (2 isolates) and S. albany (one isolate). Human serotypes isolated at the University Hospital and by the Government Bacteriological Laboratory were examined in order to note if any relationship could be detected between predominant serotypes isolated from humans and those isolated from animals and their feeds. The 10 Salmonella serotypes most frequently isolated from humans in Jamaica between 1967 and 1971 in order of frequency were: S. derby, S. typhimurium, S. infantis, S. oranienburg, S. enteritidis, S. saint paul, S. panama, S. san diego, S. heidelberg and S. anatum. There was no clear evidence of direct relationship between serotypes isolated from humans and those from food animals and their feeds. Four hundred and eighty seven food samples were examined, but none yielded Salmonella. These included poultry and pig products (sausages). The need for detailed attention towards bacteriological standards and all other aspects of the sanitary control of poultry processing plants and abattoirs was indicated (AU)