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2000 Weeks 13-25 |
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ISSN 1020-6256 AUGUST 2000 COMMUNICABLE DISEASES FEEDBACK REPORT Review Period: Epidemiologic Weeks 13-25 of 2000 A Review of Selected Diseases Acquired Immunodeficiency Syndrome [AIDS]: 1997-1999 A review of updated AIDS morbidity and mortality data for the sub-region indicates that there has been a continued worsening of this epidemic as evidenced by escalating incidence and mortality rates in CAREC member countries [CMCs]. Sub-regional incidence rates rose from 26.4 cases per 100,000 population in 1996 to 36.6 in 1999 [Figure 1]. During 1999, two thousand, one hundred and eighty six [2,186] cases of AIDS were notified to CAREC’s Epidemiology Division from 16 member countries. National incidence rates in six CMCs were in excess of 30 cases per 100,000 population, the highest recorded rate being 109.2 cases per 100,000 population [Figure 2]. Similar trends have been observed in the mortality data as overall rates rose from 17.8 deaths per 100,000 population in 1996 to 18.8 in 1998. Of the 5,455 cases occurring between 1997 to 1999, for whom gender was specified, 2,038 [37.4%] were female and 3,417 [62.6%] male. Of the 5,383 cases occurring between 1997 and 1999, for whom age was specified, 313 [5.8%] were less than 15 years of age; 463 [8.6%] were aged 15 to 24 years; 3,446 [64.0%] were aged 25 to 44 years; while 1,161 [21.6%] were 45 years or older [Figures 3a-b-c]. Of the 5,225 cases, aged 15 years and over, occurring between 1997 and1999, 3,330 or 63.7% were reportedly exposed through heterosexual contact. A modeling exercise was recently conducted as part of a series of joint technical discussions between CAREC’s Special Programme on Sexually Transmitted Infections and consultants from the US Centers for Disease Prevention and Control. Based on this exercise, it was estimated that the overall 1999 HIV sub-regional prevalence rate was in the order of 2,049 infected persons per 100,000 population, while the cumulative AIDS incidence rate stood at 253 cases per 100,000 population. The model also suggested that there could potentially be 137,000 persons currently infected with HIV in CAREC-member countries, of which 88,285 would be male and 48,048 female.
Dengue Fever During the second quarter of 2000 [epidemiologic weeks 13-25], 806 cases of dengue fever were reported to CAREC’s Epidemiology Division [Table 1; Figure 4]. The greatest proportion of these notifications [73.7%] originated from Suriname, where a large outbreak of dengue fever had been documented [Figure 5]. For the year to date, 2,057 cases of dengue fever have been reported from the sub-region, yielding an overall incidence rate of 35.3 cases per 100,000 population. A review of CAREC’s laboratory data, to date, indicates that three dengue virus types [DEN-1, DEN-2 and DEN-4] have been circulating in some CAREC member countries [CMCs]. Trinidad and Tobago was the only CMC in which all three virus-types were laboratory confirmed. DEN-2 was also isolated in the British Virgin Islands, Grenada, Guyana and Suriname, while DEN-1 was recovered in Suriname and Barbados. During the period under review, 22 patients out of a total of 320 referrals were confirmed as dengue fever by CAREC’s laboratories.
Febrile Rash Illness Surveillance During the first twenty-five weeks of 2000, one hundred and fifty-five cases of febrile rash illness were notified to CAREC’s Expanded Programme on Immunization via the Measles Elimination Surveillance System [MESS]. These patients were referred from 14 CAREC member countries. While no cases have been laboratory confirmed as measles, six were discarded as rubella from Belize and Suriname, while eight were diagnosed as dengue fever from Grenada, Suriname and Trinidad & Tobago. The initial Caribbean-wide measles catch-up vaccination campaign of 1991, together with the subsequent national keep-up and follow-up immunization initiatives have been extremely successful in eliminating indigenous measles virus transmission in the Caribbean. The need for continued surveillance cannot, however, be over-emphasized in view of the recent reports of measles infections imported into Canada. Pursuant to the resolution to eliminate indigenous rubella virus transmission as well as congenital rubella syndrome in the Caribbean, countries have embarked on adult rubella vaccination campaigns. Though coverage of the entire Caribbean target population is not complete at this time, reported rubella morbidity in the sub-region is extremely low [Figures 6 & 7].
Malaria During this review period, two fatal imported cases of malaria, one a 28 year-old female and the other was a 58 year-old male, were notified from Barbados. Both of these infections were laboratory confirmed as Plasmodium falciparum and were acquired by persons, who had recently travelled to mainland Guyana. This situation, coupled with recent reports of malaria infections imported into St. Lucia from Guyana, strongly suggests that Ministries of Health in the sub-region need to be more forceful and assertive in recommending malaria chemoprophylaxis for travellers to transmission areas in Guyana, Suriname, French Guiana and Belize. In addition, as globalization of travel escalates, all countries must constantly monitor the development of new air-links, which potentially facilitate the movement of persons between endemic, malarious and non-endemic areas. For example, the establishment of additional air services between the Cayman Islands and Honduras has contributed to an increase in the reported incidence of imported malaria into that CAREC-member country. In November 1999, nine Amazonian countries agreed, inter alia, to introduce the strategies enunciated in the Roll Back Malaria Initiative into their national action plans and to reduce the incidence of malaria among the indigenous peoples of the Rain Forest. Since the highest annual parasitological indices on the continent have been recorded in Guyana, Suriname and French Guiana, it is crucial for these countries to rapidly strengthen their national malaria prevention and control programmes. Additionally, it is imperative that effective surveillance be maintained in those countries from which malaria had been eradicated, in order to prevent its re-introduction.
Nosocomial Infection: Guyana In May 2000, a joint team consisting of staff from the Ministry of Health in Guyana and CAREC, undertook an epidemiologic investigation of a nosocomial outbreak at the neonatal unit [NNU] of Georgetown Public Hospital. The investigation revealed that the outbreak, which began in September 1999, was due to multi-resistant gram negative bacterial septicaemia. Peak transmission was observed in February 2000, when 9 cases and 5 deaths [Figure 8] were recorded. Increased transmission of the causative organism, Klebsiella pneumonia, was associated with the relocation of the NNU to the "Caesarian Mothers’ ward". During this period, significant lapses had occurred in the practice of basic hygiene essential for an intensive care unit. A review of records at the Central Medical Laboratory in Guyana revealed that in 1999, Klebsiella pneumoniae was recovered from only one of 27 blood cultures submitted for diagnosis. This isolate was cultured from an infant in the NNU in March, 1999. In contrast, however, 12 of 26 blood cultures were identified as positive for this organism, between January 1 and May 10, 2000. The antiobiogram, one of resistance to gentamicin, sulphamethoxazole and chloramphenicol, was identical in all of the Klebsiella pneumoniae isolates obtained from the neonatal unit, including the March 1999 isolate. Some degree of resistance to third generation cephalosporins was also observed. Between December 1999 and April of 2000, six isolates of Klebsiella pneumoniae with the same antibiotic resistance pattern were also recovered from the paediatric ward.
Salient Points for Reflection The findings arising out of this nosocomial outbreak as well as others, which have recently occurred in some of our member countries, reinforce the urgent need for Ministries of Health and/or Regional Health Authorities and other statutory bodies, which are now responsible for the administration of public hospitals, in a decentralized environment, to give serious attention to the area of hospital infection control.
The Public Health Laboratory In May of 2000, the enteric module of PHLIS was implemented at four laboratory sites in Jamaica, bringing to 5, the number of CMCs now participating in this network. During epidemiologic weeks 13-25, laboratory results on 374 specimens were notified to CAREC through the PHLIS network [Table 2]. Salmonella organisms were cultured from 9.0 percent of the specimens tested [33/370], while Shigella was recovered from 7 of 366 specimens. Salmonella typhi was isolated from five specimens, four of which originated in Jamaica. Three isolates of S. typhimurium were reported from Barbados. The single reported Campylobacter isolate was recovered from an 8 year-old boy in Barbados, while two isolates of rotavirus, both from children under 12 years of age, and three parasites were notified from Jamaica.
During this reporting period no weekly communicable disease reports have been received from Aruba, the Netherlands Antilles, Guyana and St. Christopher/Nevis. Dr. Merle J Lewis and team CAREC
Tables and Figures attached to this Report
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Caribbean Epidemiology Centre
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Outbreak Corner
