Epidemiological investigation for arboviruses in Jamaica, West Indies

Arbovirus investigation in Jamaica was undertaken between 1960 and 1975. Serological studies showed that antibodies to dengue type virus and St. Louis encephalitis virus (SLE) were prevalent throughout the island for several years. In urban communities, the incidence of dengue antibody was higher than for SLE; however, in children under 10 years of age antibody to both viruses was rarely present. In rural areas, SLE was prevalent in adults and children. This virus was isolated from Culex nigripalpus (mosquitoes) and from a nestling Mockingbird, Mimus polyglottos, in the same rural area. Dengue type 3 and type 4 were isolated from the sera of patients in an urban area, during two epidemic periods, 1963 and 1968. No other group B arbovirus was encountered on the island. Group A arbovirus was virtually absent prior to the eastern equine encephalomyelitis outbreak of 1962. That virus was isolated from brain tissue of human and equines. Two strains of Cache Valley virus from mosquitoes, Anopheles grabhami, one strain from Aedes taeniorhynchus, and a strain of Wad Medani virus from a tick, Amblyomma cajenense, were also isolated (AU).

Epidemiological investigation for arboviruses in Jamaica, West Indies

Arbovirus investigation in Jamaica was undertaken between 1960 and 1975. Serological studies showed that antibodies to dengue type virus and St. Louis encephalitis virus (SLE) were prevalent throughout the island for several years. In urban communities, the incidence of dengue antibody was higher than for SLE; however, in children under 10 years of age antibody to both viruses was rarely present. In rural areas, SLE was prevalent in adults and children. This virus was isolated from Culex nigripalpus (mosquitoes) and from a nestling Mockingbird, Mimus polyglottos, in the same rural area, during two epidemic periods, 1963 and 1968. No other group B arbovirus was encountered on the island. Group A arbovirus was virtually absent prior to the eastern equine encephalomyelitis outbreak of 1962. That virus was isolated from brain tissue of humans and equines. Two strains of Cache valley virus from mosquitoes, Anopheles grabhami, one strain from Aedes taeniorhynchus, and a strain of Wad Medani virus from a tick, Amblyomma cajenense, were also isolated (AU)

The use of the R/B tubes in diagnostic bacteriology

The modified R/B, two-tube, rapid identification system was compared with conventional biochemical tests in the identification of 500 strains of different members of the Enterobacteriaceae. The R/B tubes identified 97 percent of the organisms conclusively within 18 hours, the reactions being generally easy to read and interpret. No special skill was required for the use of the media or interpretation of the results. Most of the atypical strains were, however, incorrectly categorized at first screening. R/B tubes are expensive but with the time saved in media preparation, washing and sterilization of glassware and with fewer tubes to inoculate, also with savings in bench and refrigerator space and less need for quality control of media, the expense may be more apparent than real (AU)

Clinical gonorrhoea in the female: laboratory findings

The practice of treating females with vaginal discharges and other pelvic symptoms, on the basis of a presumptive diagnosis of "Clinical gonorrhoea" without attempting to obtain adequate laboratory tests for N. Gonorrhoea, T. Vaginalis and C. Albican in female patients. All of whom had reported to a V. D. Clinic, (some because they were reported as contacts of male gonorrhoea patients), and who had been selected for penicillin treatment. All had vaginal discharges and other evidence of genital disease. The study was carried out at the Comphrensive Health Centre in Kingston, Jamaica. Tests for Gonorrhoea included cervical and vaginal gram-stained smears and cervical cultures. Due to shortages of media and personnel, cultures for the comparison of smear and cultures involved, for about half of the female studied, a single Transgrow bottle culture from the cervix and for the other half a Transgrow bottle culture and also a small (5.5cm) Thayer-Martin plate. Other patients had a rectal culture on a small Thayer-Martin plate also. These were included not alo in the comparison of results with overall tests for N. Gonorrhoea, E. Baginalis and C. Albicans. Transgrow cultures were incubated immediately. Tests for T. Vaginalis included wet preparations and cultures on "Trichomonas medium". Tests for C. Albicans involved cultures on Sabouraud's agar with yeast identified as C. Albicans by the germination test as described by Taschdjian and associates. A total of 107 or 45.9 percent of 233 females had positive tests for gonorrhoea. (In three of these the test were doubtful). 104 or 44.6 percent had positive tests for T. Vaginalis; 72 or 30.9 percent had positive tests for C. Albicans. Overall, 187 patients or 80.2 percent were positive (or doubtful) to one or more tests and 46 or 19.8 percent were negative to all three. Patients with mixed infections were: N. gonorrhoea + T. Vaginalis - 15.4 percent, n. gonorrhoea + C. Albicans - 7.3 percent, N. gonorrhoea + C. Albicans T. Vaginalis - 6.4 percent, T. Vaginalis + C. Albicans - 5.6 percent. Of 92 or 41.8 percent of a total of 220 females studied, and who were positive or doubtful, only 40 or 18.2 percent of the total had positive or doubtful smears, while 52 or 23.6 percent of the total had only positive cultures. The latter would have been missed had smears alone been done. (i.e. 56.5 percent of cases). Of 94 or 44.3 percent of 212 females studied by T-M and Transgrow media, 76 had both tests positive. A total of 18 had one test positive, 7 with Transgrow and 11 with T-M. Of 104 patients who had both rectal and cervical cultures, 8 or 7.7 percent had only the rectal culture positive. There were 23 positive rectal cultures compared with 51 cervical positives out of a total of 59 with positive cultures. Of 140 patients with Trichomonal infestation, 107 had positive wet preparations while 114 had positive cultures. The advantage of culture over wet preparation is therefore but slight. It is clear that smears are inadeqate as anything more than supplementary diagnostic aids and that cultures for gonorrhoea are absolutely essential in the diagnosis of gonorrhoea in the female. Rectal cultures were found to add substantial increase (15.7 percent) to the number of positive cases when used in conjunction with cervical cultures. This must be clear to all physicians and cultures made available for their use(AU)

Simultaneous vaccination against cholera and yellow fever

A study of serum-samples from immunised individuals showed that administration of yellow-fever and cholera vaccine, simultaneously or one to three weeks apart, reduced the vibriocidal and yellow-fever-virus-neutralising antibody titres (AU)

Clinical gonorrhea in the female: laboratory findings

This paper is very timely in its relationship to the current epidemic of gonorrhea in this country and as reported by the western nations. It emphasizes the difficulty in establishing the diagnosis of gonorrhea in women and girls without using cultures from the cervix and rectum. The new media soon available to the practising profession will be a boon in this regard. Mixed infections or infestations have been proven in instances of vaginitis. The smear is of little value alone. This study does not touch upon the high percentage of women infected with gonorrhea who are asymptomatic. (AU)

Trials with a live attenuated rubella virus vaccine, Cendehill strain

This report summarizes closed, family, and open studies conducted sequentially over a 10 month period with the Cendehill rubella virus vaccine in more than 16,000 children and adolescents. This strain of rubella was attenuated by serial propogation on primary rabbit kidney cell cultures. Inoculation of the Cendehill vaccine produced seroconversion in 97 percent of the 3589 susceptible (seronegative) vaccinated persons. There was no spread of the virus to susceptible controls living in close contact with those vaccinated. The vaccine was well tolerated. No arthritis or arthralgia occured in 860 female subjects 13-18 years of age who were included in the study. The Cendehill vaccine would appear to meet the requirements of an acceptable vaccine (Summary)

Clinical and laboratory findings in dengue fever cases in Jamaica and the possible implications

Clinical and laboratory investigations of dengue fever cases in 1969 revealed no minor or major haemorrhagic phenomena, although the serological response of over two-thirds of confirmed cases was the 'secondary' type reaction, indicating reinfection. Dengue virus type 2 was the agent of infection whereas in 1968, when only 25 per cent cases showed a 'secondary' antibody response the infective agent was predominantly Dengue virus type 3. It is interesting to note that Dengue virus type 3 was also most likely responsible for the 1963 epidemic of Dengue-like illness. Now for the first time, there is indisputable evidence of the occurrence of a second dengue serotype (Dengue type 2) which most likely infected a large number of persons who had previously been infected, presumably, by Dengue type 3 - the latter being the only other type found in the island. It has been suggested that prior dengue virus infection sensitises some patients, who, on reinfection by a different dengue virus serotype, develop Dengue haemorrhagic fever and/or Dengue shock syndrome. These severe manifestations of dengue virus infections have been quite common in children of South-East Asia within the last two decades. Fortunately, these haemorrhagic phenomena have not occurred in Jamaica, although the basis for their occurrence seems to be present. It is important to note that reinfection by a different dengue virus serotype is a relatively recent feature of dengue disease in this country (AU)

Recurrent dengue fever in Jamaica - abstract

From clinical and serological evidence, dengue is believed to be endemic in Jamaica. However, no positive confirmation had been made of this fact because the virus had not been isolated and St. Louis Encephalitis virus, a close serlogical relative of dengue, is known to be present in the island. Certain communities in the island were known to have an incidence of dengue antibody as high as 60-70 percent. Nevertheless, during the 1963 outbreak these communities suffered a high incidence of infection second only to the Kingston and St. Andrew area. Again in 1968, the Kingston and St. Andrew population was heavily affected and in some instances persons complained of having dengue twice within months. Most of our clinical cases were adults. Between January, 1968 and January, 1969, a total of 679 cases was reported. 112 of 175 tested were proved serologically to be due to recent infection. Using challenge virus resistance technique in AGMK and BSC-1 cells with echo 9 and polio 1 as challenge viruses, 20 agents were isolated. Nineteen of these were from human sera and one from a pool of Aedes aegypti mosquitoes. 31 human sera were inoculated into one-day Swiss white mice. On 14 occasions symptoms indicative of viral infection were seen. Some of our isolates have been confirmed by plaque techniques in LLC-MK2 and PS continuous pig kidney cell lines. The rapid development of high serological titres seen in individuals with classical dengue symptoms suggests a secondary immune response. This is in contrast to cases in which dengue symptoms were associated with moderate conversions, presumably primary infections. In two cases virus was isolated from specimens with coexisting dengue antibody. During the earlier part of 1968 typical symptoms were fever, joint and retro-orbital pain with occasional rash. During the latter half of the year nausea and severe abdominal distress became prominent while the rash became more frequent and total, appearing even on the palms of the hands and soles of the feet. The significance of these observations is not clearly understood, but they could bear comparison with situations reported from the Far East. There, repeated infections have resulted in extremely severe "Dengue symptoms", haemorrhage, shock and death (AU)

Clinical trials in Jamaica with the cendehill rubella vaccine - abstract

This paper presents our findings from a closed study involving 54 children, a family study involving 100 families and an open study involving more than 16,000 children, ages five years to 15 years, in an urban area in Jamaica. The vaccine produced good immunogenic response and did not spread the disease to susceptible controls in contact with the vaccinees. Our experience with the Cendehill rubella vaccine has shown that it has all the requirements of an acceptable vaccine. It produced sero-conversion in a large percentage of sero-negative vaccinees; it did not spread the disease to sero negative controls living in close contact; it produced only mild side effects in childern, and there was no evidence of arthralgia or arthritiis in vaccinees(AU)

Human salmonellosis in Jamaica 1962-1966

Human salmonella isolates in Jamaica during the period 1962-66 have been reviewed. There were 843 isolates of S. typhi and 552 isolates of other salmonella serotypes in this five-year period. Type E1 continued to be the most prevalent typhoid Vi phage type. S. typhimurium accounted for approimately 35 percent of non-typhi salmonella isolates. The number of S.infantis isolates has risen markedly since 1963. Examination of some of the epidemiologic features of salmonellosis in Jamaica showed that the apparent incidence of typhoid fever, as judged by reported cases, reported deaths, and number of isolates, declined over the past decade. There has been no discernible trend in the yearly frequency of isolates of other serotypes. As elsewhere, the majority of isolates are from children. The peak age-incidence of laboratory confirmed S. typhi infections is in the 5-9 age group; for other salmonelloses the peak is in children less than 1. The seasonal distribution of non-typhi salmonella isolates presents abi-modal curve with peaks in April and October. These peaks correspond roughly to the two Jamaican rainy seasons. The significance of this finding, if any, remains to be elucidated (AU)

An epidemic of dengue-like illness in Jamaica - 1963

In June 1963 an outbreak of a dengue-like illness occurred in Jamaica. The only recorded dengue epidemic in Jamaica before that of 1963 had been in 1824, as mentioned in church records of causes of death. Over 450 primary inoculations of serum from acutely ill patients and from mosquitoes associated with them were made in animals and in tissue-cell cultures. A possible isolation was made in one cell culture inoculated with material from Aedes aegypti mosquitoes, as evidenced by interference studies. Otherwise, no isolation was made, although inoculated suckling mice gave signs of disease of the central nervous system. The characterization of the epidemic as "dengue-like" was based upon the clinical course of patients and upon serological findings. (Summary)

Surveillance of eastern equine encephalomyelitis (EEE) in Jamaica

Since the outbreak of EEE in Jamaica in 1962, a continued surveillance for the virus has been maintained. It is known that birds act as reservoirs for the virus, and mosquitoes as vectors, consequently our attention directed towards ornithological and entomological investigations. Mosquitoes were caught regularly in the St. Thomas area during and after the outbreak. The surveillance among birds started some months later, and has continued to the present time. No mosquito was found infective with EEE virus, but Cache Valley virus, which is and arbovirus, was isolated from mosquitoes in the area. During the outbreak several birds (including domestic chickens) were bled and tested for circulating virus as well as for antibody to EEE virus. Fourteen of the 356 sera collected within six weeks after the outbreak showed a significant neutralizing titre to EEE virus. Among the wild birds caught subsequently, three of them (one resident and two migrants) showed sero-logical conversion to EEE virus in the St. Thomas area. About one year ago, the programme was extended to include the Black River area in St. Elizabeth. One bird in this area showed partial protection to EEE virus. These results seem to indicate that EEE virus is either endemic in the areas tested, or has been re-introduced by migrant birds. It is therefore necessary to maintain a continued surveillance to detect any activity of this virus(AU)

Recent investigations of leptospirosis in Jamaica

The epidemiologic, clinical and laboratory features in Jamaica of a series of 50 cases of leptospirosis collected at the diagnostic laboratory of the Department of Microbiology - U.W.I. are reviewed. Infections occurred in most of the parishes of the island and were associated with a wide range of occupations. Forty-six (46) of these patients were hospitalized at the University Hospital W.I. and a total of 9 isolates were made. Three of the patients (all with positive cultures) were from the Monymusk Sugar Estates and one was hospitalized elsewhere. The serotypes identified from these isolates were Icterohaemorrhagiae, Jules, Kremastos and Abramis. The age distribution ranged from 10 to 70 years of age: there were 35 males and 15 females. Each serotype seemed capable of producing a wide variety of clinical features. The serotypes most commonly diagnosed in the laboratory by the microscopic and macroscopic tests were Leptospira Icterohaemorrhagiae, Canicola, Jules Pomona and Abramis. The highest titre observed wa 1:3200 in the serotype L. Icterohaemorrhagiae. Experience gained and continued work in the field of Leptospirosis over the past few years indicate that the Leptospires are a more common infection of man and animal that was formerly realized(AU)

The treatment of intestinal amoebiasis with a single dose of humatin

Humatin was well tolerated, and eliminated E. histolytica infection as determined by stool examination in sixty percent of cases. The drug appeared to be more effective in older individuals than in those under eight years of age. It eliminated abdominal cramps, fever, nausea, vomiting and weakness in most cases in which these symptoms were present before treatment (AU)