A review of CAREC’s laboratory data for weeks 1 through 38 of 1999 indicates the continued circulation of DEN-1, DEN-2 and DEN-3 virus types in some CAREC Member Countries [CMCs]. Barbados is, however, the only member country in which all 3 dengue serotypes have been documented, to date. Dengue virus type 1 was laboratory confirmed in St. Lucia and Suriname; virus type 2 was documented in Trinidad and Tobago and Grenada, while the type 3 virus was isolated in St. Christopher/ Nevis and Belize. The presence of DEN-3 has been confirmed and notified to us from Aruba.

Additional review of data contained in CAREC’s Laboratory Information System [LABIS] as at December 23, 1999, reveals that there were 200

confirmations out of the 1175 requests made for laboratory diagnosis of dengue fever. It is further noted that both the numbers of test requests and laboratory confirmations of dengue fever increased significantly from the month of September [Figure 2]

Data received from the French Caribbean Team [CIRE] of the National Institute for Public Health Surveillance [InVS] indicates that dengue virus transmission peaked in Martinique during the month of September [Figure 3]. This increase was detected both by the physician-based and laboratory-based surveillance systems. Only sporadic dengue virus activity was reported from Guadeloupe and Guyana. No cases of DHF/DSS were notified by the French departments during the period under review.

While there has been an overall decrease in reported dengue fever morbidity during 1999 as compared with previous years, the need for continued vigilance remains. Laboratory-based surveillance systems must be strengthened in order to provide, firstly, early detection of circulating serotypes and to guide recurrent and emergency intervention measures. Secondly, such data is also required to facilitate meaningful epidemiological description of susceptibility and immunity patterns in populations in order to better understand the potential disease risks.

In the absence of a vaccine, dengue virus transmission can only be reduced through mosquito control. However, the community must partner with the government in order to ensure that the control programmes are effective and sustainable.

On December 23, 1999, CAREC was notified by the Cellule Inter Regionale d’Epidemiologie [CIRE] of the confirmation of an indigenous dengue type 3 virus infection in a 36 year old career soldier, who had been resident in Martinique for the past 4 months. This case represents the first documentation of this virus type in the French Departments in the Caribbean.

During the period under review, 11,055 cases of influenza were reported to CAREC’s Epidemiology Division as compared with 20,211 cases for the corresponding period in 1998 [Table 1]. The non-receipt of weekly communicable disease reports from Suriname during this reporting period contributed to this significant apparent decline. However, of the 18 CAREC member countries recording cases of influenza during this period, 1 experienced increased morbidity over that observed for the corresponding period of 1998 [Figure 4]. Grenada, the country with the largest percentage increase, reported 205 cases of influenza during the period under review, as compared with 21 cases for the corresponding period of 1998. CAREC’s laboratories recovered a single virus isolate from Grenada, which was characterised as influenza A[H3N2] by the US Centers for Disease Control and Prevention.

Between March and September 1999, many countries in the Northern hemisphere reported sporadic influenza activity, while epidemics were recorded in South america (Argentina, Brazil, Chile, Uruguay) [WHO-FLUNET] [WHO-FLUNET]. Although both influenza A and B viruses were frequently isolated, A[H3N2] was the predominant aetiologic agent circulating in most countries ]. Although both influenza A and B viruses were frequently isolated, A[H3N2] was the predominant aetiologic agent circulating in most countries [WHO WER 1999, 39 :321-328].

Active consideration must be given to the establishment of laboratory based influenza surveillance in the Caribbean in order to facilitate the early detection of newly introduced serotypes.

Five thousand and fifty one (5,051) cases of acute respiratory infections among children less than five years of age were notified from 12 CMCs during this reporting period. During the corresponding period of 1998, 3,194 cases were reported from 10 CMCs. Notable increases were recorded in Anguilla, Antigua, Belize, St. Vincent & the Grenadines and the Turks & Caicos Islands, all of which had also reported increased morbidity due to influenza during the same period.

Of the twenty (20) suspected cases of typhoid fever reported to CAREC’s Epidemiology Division during the period under review, 19 were notified from Jamaica. Seventeen of these cases were recorded between epidemiologic weeks 30 and 33. Investigation of these suspected cases, however, resulted in eleven being confirmed. A familial cluster of five cases was associated with use of river water.

An Outbreak of a West Nile-like Virus: The Unites States of America

An outbreak of a West Nile-like virus was reported during the period under review in the eastern coast states of the USA. As at September 28, a total of 17 confirmed and 20 probable human cases with 4 fatalities had been documented in the New York City outbreak. Most of the severe clinical cases and all of the fatalities had occurred among older persons [US CDC's MMWR of October 1, 1999][US CDC's MMWR of October 1, 1999]. This West Nile-like virus was also identified in dead birds in New York State as well as in mosquitoes and birds in southern areas of the State of Connecticut. The outbreak in New York was successfully controlled through extensive aerial and ground applications of mosquito adulticides and larvicides.

West Nile [WN] virus is member of the antigenic complex of flaviviruses [Group B arthropod-borne viruses] which includes the Murray Valley, St. Louis and Japanese B Encephalitis viruses. It is known to occur naturally in Africa; the Middle East, where it has been most studied in Egypt; parts of Europe; the former USSR; India and Indonesia.

WN fever is a zoonosis that is transmitted from birds to man and other mammals by ornithophilic [bird-feeding] mosquitoes. The potential for spread of this West Nile-like virus from North America to the Caribbean and South America via migrating infected birds is a real possibility.

A surveillance system for travel associated Legionnaire’s Disease has been established by the European Working group on Legionella Infections [EWGLI] to identify cases of legionella infection among returning travelers and to detect outbreaks and clusters of legionnaire’s disease. Thirty-one European countries are now participating in this network. In some countries, representatives of national tour-operator organizations are informed of cases that arise in tourist accommodations.

Between 1997-98, two clusters of cases were detected in tourists returning from the Caribbean [Eurosurveillance, Vol.4, N°11][Eurosurveillance, Vol.4, N°11].

Due to the large and increasing quantum of travel from European countries and the potential for legionella transmission that exists in tourist resorts in the Caribbean, it is important for hotel physicians and nurses to communicate their clinical suspicions to their national epidemiologist as soon as possible, in order to ensure, inter alia, that there is timely and appropriate follow-up of suspected cases and that efficient control and surveillance measures are rapidly implemented.