Seroepidemiology of feline leukaemia and feline immunodeficiency virus in domestic and feral cats in Grenada.

The serological prevalence of feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) infections in domestic and feral cats in Grenada was studied using serum samples collected from 237 cats. The serum samples were tested for antibodies to the two viruses with the IDEXX ninety-six well micro assay plate ELISA kits. For confirmation, positive samples were further tested with the IDEXX comb FIV and FeLV snap tests. The overall prevalence of FeLV and FIV in cats in this study was 0% (n=237) and 19% (45/237), respectively. The seroplrevalence of FIV was 6.7% (7/104) in domestic cats and 28.6% (38/133) in feral cats. Feral cats had a significantly (p<0.05) higher FIV seroprevalence than domestic cats, and there was a significantly greater FIV seroprevalence in males compared to females as well as in cats 1 year of age and older compared to cats under one year. This study establishes the prevalence of FIV infection in Grenada. The negative FeLV results in our study are probably a reflection of Grenada's relative isolation and lack of numerous amicable contacts that occur when many cats share a close living space.

Seroepidemiology of feline leukaemia and feline immunodeficiency virus in domestic and feral cats in Grenada.

The serological prevalence of feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) infections in domestic and feral cats in Grenada was studied using serum samples collected from 237 cats. The serum samples were tested for antibodies to the two viruses with the IDEXX ninety-six well micro assay plate ELISA kits. For confirmation, positive samples were further tested with the IDEXX comb FIV and FeLV snap tests. The overall prevalence of FeLV and FIV in cats in this study was 0% (n=237) and 19% (45/237), respectively. The seroplrevalence of FIV was 6.7% (7/104) in domestic cats and 28.6% (38/133) in feral cats. Feral cats had a significantly (p<0.05) higher FIV seroprevalence than domestic cats, and there was a significantly greater FIV seroprevalence in males compared to females as well as in cats 1 year of age and older compared to cats under one year. This study establishes the prevalence of FIV infection in Grenada. The negative FeLV results in our study are probably a reflection of Grenada's relative isolation and lack of numerous amicable contacts that occur when many cats share a close living space.

Direct migration inhibition with measles antigen effect of measles vaccination

The direct migration inhibition (DMI) assay with measles antigen was performed on leukocytes from 24 Trinidadian children both before and after measles vaccination. The children had no clinical history or serological evidence of measles before vaccination. After vaccination, the measles (HI) antibody titer (geometric mean titer) rose to 1:128. Despite the lack of prior measles exposure, migration inhibition to the antigen was high before vaccination and did not significantly differ from migration inhibition after vaccination. This finding suggests that reactivity to measles in the DMI assay is probably nonspecific and does not depend on prior exposure to measles. (AU)

Immune responses during human schistosomiasis mansoni. III. Regulatory effect of patient sera on human lymphocyte blastogenic responses to schistosome antigen preparations

The in vitro lymphocyte blastogenesis capabilities of patients with schistosomiasis mansoni were tested against phytohemagglutinin (PHA), Candida albicans extract,and soluble preparations of schistosome eggs (SEA), adult worms (SWAP), or cercariae (CAP). When patients lymphocytes were cultured un medium which contained 5 percent human (homologous) normal (uninfected) serum, they responded well to PHA and Candida extract. The responses induced by SEA were maximal in patients with early Schistosma mansoni infections, while reactivity against SWAP and CAP increased during chronic infection. These responses, induced by the Schistosome-derived antigenic preparations,were suppressed if the homologous normal serum supplement of the culture medium was replaced with either the patient's own (autologous) serum, or that of another S. mansoni patient. All sera were heat-inactivated (56 degree C/ 30 min) prior to use. In contrast, responses against the non-specific mitogen (PHA) and the unrelated antigen (Candida extract), were not altered by these changes of the serum supplementation of the media. The degree of suppression by patient serum was not changedby increasing the serum percentage in the medium from 5 percent to 25 percent. The suppressive effects of patient sera on responses induced by SEA and SWAP were increased in relationship to the duration of the serum donor's S. mansoni infection. Preincubation of lymphocytes in suppressive patient sera for 30 min at 37 degree C did not reduce the expected level of responsiveness if the cells were subsequently cultured in homologous-normal serum supplemented medium. The data indicate that during S. mansoni infection patients develop serum component(s) which specifically interfere with the responsiveness of their lymphocytes in regard to certain schistosome-derived antigenic preparations. The immunoregulatory events described could participate in the modulation of immunopathology, the maintenance of chronic worm survival and the prevention of full expression of protective immune responses. (AU)

Immunological studies on leakage of heart antigens in Jamaican cardiomyopathies

Antibodies to cow-heart tissue were prepared in mice. These antibodies were used to demonstrate the presence of cardiac antigens in sera of patients with cardiac disease. Normal individuals gave positive reactions, but to a lesser extent (AU)

Recovery of dengue-2 and dengue-3 viruses from man in Jamaica

Dengue-like illness has been reported in Jamaica since 1824, although the viruses concerned were never isolated. The emphasis of this work was isolating and typing the etiologic agents involved; 679 cases were reported to the Microbiology Department, University of the West Indies, during 1968 and 1969. Primary serum samples were tested; 112 of 175 indicated recent arbovirus group B infections. Primary infections and reinfections with dengue viruses were indicated by hemagglutination-inhibition and complement-fixation tests. Challenge-virus resistance technique was used to isolate eight agents from human serum. Six of these strains have been typed as dengue-3 and two as dengue-2 viruses.(AU)

Persistent impairment of insulin secretion and glucose tolerance after malnutrition

Oral glucose tolerance tests on Jamaican children after an average of 3 months treatment in a hospital for malnutrition suggested a diminished peripheral uptake of glucose. This was confirmed with intravenous glucose tolerance tests. Despite 3 months treatment on an optimal diet the children's plasma levels of immunoreactive insulin were still subnormal, and the insulin response to intravenous glucose was much less than in Jamaican children who had never been malnourished. This suggests that malnutrition may produce a permanent reduction in the capacity for insulin secretion (AU)

Nonspecific reactions to casoni antigen

Animal-derived hydatid-fluid antigens, principally Australian commercial antigen, were skin tested in Puerto Ricans, other persons of Caribbean origin, and in native-born New Yorkers. The findings suggested that there existed a certain previously unreported degree of cross-reactivity to Casoni antigen in persons with schistosomiasis and possibly in nematode parasitic infections. Geographic matching of controls with cases would, therefore, be necessary in order to determine the usefullness of parasitic skin-test antigens, and the results of population surveys with these antigens would have to be interpreted cautiously. Interpretation of Casoni skin tests with commercial antigens must be made in the light of cross-reactions in persons exposed to other helminth infections. A human-derived antigen, and an animal-derived antigen of low nitrogen content, did not appear to possess any considerable advantage over those that are commercially available (AU)

Characteristics of beta hemolytic streptococci associated with acute glomerulonephritis in Trinidad, West Indies

Twenty-seven strains of beta hemolytic streptococci from patients with acute glomerulonephritis and 212 strains from school children were isolated in Trinidad during an epidemic of nephritis involving over 1,000 patients. Sixty-two per cent of the 27 strains from nephritic patients and 3 strains from school children belonged to an apparently new serotype referred to here as Trinidad type A. Type-specific antibodies against this type were found in 50 per cent of 56 patients 1 to 3 months after acute glomerulonephritis. Six of the 10 remaining strains from patients with nephritis and 34 strains from school children were characterized as a second new type B. This strain contained M protein of provisional type Schoenborn isolated from pyoderma in Red Lake, Minnesota. It also contained a second antigen found in some type 41 strains of streptococci. Studies of temperate bacteriophage related to these strains suggested a possible association with nephritis in a negative way. With one exception, streptococci strains from nephritic patients were not lysogenic, while antiphage activity was observed in sera from 72 per cent of 50 patients. Moreover, 33 per cent of 86 strains from school children in areas where nephritis was occurring were lysogenic, while only 3 of 46 strains from areas without nephritis contained bacteriophage.(AU)