Full genomic characterization of a novel genotype combination, G4P[14], of a human rotavirus strain from Barbados.

Since 2004, the Pan American Health Organization (PAHO) has carried out rotavirus surveillance in Latin America and the Caribbean. Here we report the characterization of human rotavirus with the novel G-P combination of G4P[14], detected through PAHO surveillance in Barbados. Full genome sequencing of strain RVA/Human-wt/BRB/CDC1133/2012/G4P[14] revealed that its genotype is G4-P[14]-I1-R1-C1-M1-A8-N1-T1-E1-H1. The possession of a Genogroup 1 (Wa-like) backbone distinguishes this strain from other P[14] rotavirus strains. Phylogenetic analyses suggested that this strain was likely generated by genetic reassortment between human, porcine and possibly other animal rotavirus strains and identified 7 lineages within the P[14] genotype. The results of this study reinforce the potential role of interspecies transmission in generating human rotavirus diversity through reassortment. Continued surveillance is important to determine if rotavirus vaccines will protect against strains that express the P[14] rotavirus genotype.

Distribution of influenza and other acute respiratory viruses during the first year after the 2009-2010 influenza pandemic in the English- and Dutch-speaking Caribbean countries.

BACKGROUND: Limited specimen collection and testing for influenza occurred in the English and Dutch-speaking Caribbean countries prior to the 2009/2010 influenza pandemic. Caribbean Epidemiology Centre (CAREC) member countries rapidly mobilized to collect specimens during the pandemic and a vast majority of confirmed cases during the pandemic period were influenza A(H1N1)pdm09. OBJECTIVES: To describe the aetiology and distribution of acute respiratory illness (ARI) among laboratory confirmed cases during the first year after the 2009/2010 influenza pandemic in the English- and Dutch-speaking Caribbean. RESULTS: In total, 774 specimens were tested and 394 (52.7%) cases had positive laboratory confirmation. Respiratory syncytial virus (RSV) (28.4%) and influenza A(H3N2) (23.1%) were most frequently detected. RSV activity peaked in July 2011 while influenza A(H3N2) peaked in October 2010. Influenza was responsible for illness in greater numbers in persons 15-64 years while RSV was seen in primarily in children<5 years and adults>65 years. Other agents confirmed include rhinovirus (12.9%), influenza B (10.9%) and influenza A(H1N1)pdm09 (9.4%). CONCLUSIONS: RSV and influenza A(H3N2) were the most common viruses identified during the first year after the influenza A(H1N1)pdm09 pandemic. Influenza was detected every month with peak activity corresponding to that typically seen in North America (October to March). In order to determine the seasonality of influenza and RSV, laboratory data from subsequent years and increased specimen submission is needed.

Genotyping of rubella virus RNA in sera and dried blood spots collected during routine surveillance and in archival sera.

Information on the molecular epidemiology of rubella has been valuable in supporting efforts to control and eliminate rubella in several countries. The preferred samples for virus isolation or RNA detection, such as throat swabs, are often not available making it difficult to obtain a robust database of rubella virus sequences. A method for obtaining rubella virus genotypes from more commonly collected samples such as sera or dried blood spots using real-time RT-PCR to screen samples followed by nested set amplification is described. Rubella genotypes were obtained from dried blood spots and recent and archival sera collections. Eighteen percent of the RNAs extracted from the archival sera were real-time RT-PCR positive, and 44% of these RNAs were amplified successfully by nested RT-PCR and sequenced. Implementation of this technique could provide another tool to improve global rubella molecular surveillance.

Lessons learned from integrated surveillance of measles and rubella in the Caribbean.

The Caribbean subregion was one of the first areas to successfully integrate measles and rubella surveillance, and it can serve as an example to other subregions on how to achieve similar success. The integrated surveillance system, established through strong political commitment by Caribbean countries, is coordinated by the Caribbean Epidemiology Centre (CAREC). The system, which became operational in January 2000, is designed to detect and investigate patients with fever and rash illness, and also test a blood specimen from each case investigated. During over 9 years of operation, 3733 cases were reported and investigated. Laboratory tests identified 2 imported cases of measles, 27 cases of rubella, 309 cases of dengue, and 260 cases of human herpesvirus 6 (HHV-6) infection. The lessons learned from the success of this integrated system indicate that the following factors are critical: strong political commitment, strong technical oversight from all levels within the health-care system, the use of proven tools or systems and technology for data collection and analysis, integration with other surveillance activities, continuing training, and continuing review and evaluation.

The Measles Laboratory Network in the region of the Americas.

The success of measles eradication depends upon a laboratory network to rapidly analyze samples obtained as part of surveillance and case investigation. The Pan American Measles Laboratory Network was established in 1995. Major activities of the 22 participating laboratories include the rapid testing of serum samples to diagnose measles, analysis and recommendation of techniques to be used in serologic testing, training in virus isolation, and procurement and distribution of laboratory materials. In addition, a comprehensive quality-control program and an electronic communication network have been developed. Testing for rubella has also been incorporated. The Network has been crucial to the great progress made toward eradicating measles from the Western Hemisphere. The priority given to the laboratories in the Network must continue in order to ensure that the eradication goal is reached and that validation of the interruption of endemic transmission of measles is documented.

Integrating measles and rubella surveillance: the experience in the Caribbean.

In 1988, the Ministers of Health in the Caribbean Community resolved to eliminate cases of indigenous measles. Specific performance indicators were developed to regularly monitor the program. In 1998, selected countries in the Caribbean elected to accelerate rubella control. As a first step, surveillance for both measles and rubella was integrated, using the measles eradication system as a template. Between 1995 and 2000, 98%-99% of the surveillance sites reported weekly. During that time, the number of suspected measles and rubella cases that were disqualified by laboratory testing remained relatively constant at 94%-99%; however, the indicator for suspected cases investigated within 48 h improved from 89% in 1996 to 95% in 2000. This integrated surveillance system has thus proven to be as effective and efficient as the measles surveillance system alone. Limited changes were made to the initial measles system, and the transition was relatively smooth. The integrated system has been crucial to the control of rubella and for the maintenance of measles elimination in the Caribbean.

Outbreak of poliomyelitis in Hispaniola associated with circulating type 1 vaccine-derived poliovirus.

An outbreak of paralytic poliomyelitis occurred in the Dominican Republic (13 confirmed cases) and Haiti (8 confirmed cases, including 2 fatal cases) during 2000-2001. All but one of the patients were either unvaccinated or incompletely vaccinated children, and cases occurred in communities with very low (7 to 40%) rates of coverage with oral poliovirus vaccine (OPV). The outbreak was associated with the circulation of a derivative of the type 1 OPV strain, probably originating from a single OPV dose given in 1998-1999. The vaccine-derived poliovirus associated with the outbreak had biological properties indistinguishable from those of wild poliovirus.

Molecular diagnosis of dengue by reverse transcriptase-polymerase chain reaction

The techniques of reverse transcriptase-polymerase chain reaction (RT-PCR) and subsequent PCR were employed in the analysis of serum samples from a range of patients from the Caribbean Epidemiology Centre (CAREC) member countries. Results were compared with those from viral isolation and immuno-fluorescence. In the second part of the study, ten serum samples were stored for one week under four sets of conditions: -20 degrees C, 4 degrees C, 25 degrees C, and thawed (20 degrees C) and frozen (-20 degrees C) daily. After one week of each treatment the samples were analysed by RT-PCR and PCR. 90.4 percent of results from PCR agreed with results from viral isolation (VI) and fluorescent antibody (FA) detection. All PCR positive samples originated from sera collected within five days of the date of onset of fever. Frozen, refrigerated and repeat freeze-thawed samples gave consistent positive results by RT-PCR. The results indicate the sensitivity and reliability of this rapid technique and its applicability in the Caribbean. It provides a preliminary assessment of its advantages and limitations under certain conditions of serum collection and storage (AU)

Molecular diagnosis of dengue by reverse transcriptase-polymerase chain reaction: a new tool for rapid diagnosis of dengue infection in the Caribbean

The techniques of reverse transcriptase polymerase chain reaction (RT-PCR) and subsequent PCR were employed in the analysis of serum samples from a range of patients from CAREC member countries (CMCs). Results were compared with those from viral isolation and immunofluorescence. In the second part of the study, ten serum samples were stored for one week under four sets of conditions: 20 degree C, 4 degree C, 25 degree C, and thawed (20 degree C) and frozen (-20 degree C) daily. After one week of each treatment the samples were analysed by RT-PCR and PCR. The results from PCR correlated 100 percent with results from viral isolation (VI) and fluorescent antibody (FA) detection. Where the date of onset of fever was reported, all PCR positive samples originated from sera collected within five days of this date. Frozen, refrigerated and repeated freeze thawed samples gave consistent positive results by RT-PCR. After storage at 25 degree C, however, half the dengue-positive samples were negative by RT-PCR. The results indicate the sensitivity and reliability of this rapid technique, its applicability in the Caribbean, and an idea of its limitations under certain conditions of serum collection and storage.(AU)

Chlamydia trachomatis in antenatal women at Mount Hope Women's Hospital in Trinidad and Tobago: prevalence and perinatal transmission

Chlamydia trachomatis infection is being increasingly recognized as an important public health problem worldwide. The prevalence and rate of perinatal transmission of chlamydia was examined in 200 women attending antenatal clinic at the Mt. Hope Women's Hospital using tissue culture (TC), ELISA and fluorescent antibody (FA) methods. 27 (13.6 percent) women were found to be chlamydia positive by TC. 13 of the babies born to these mothers were also found to be positive, giving a vertical transmission rate of 48 percent. Compared to TC, the ELISA test was 96 percent sensitive and 100 percent specific while FA was 67 percent sensitive and 99 percent specific. Chlamydial infection was significantly associated (p<0.001) with being of Afro-Trinidadian descent, age <25 years, being unmarried and having two or more sexual partners in the past five years. The association with ethnicity could be explained on the basis of numbers of sexual partners and marital status. Chlamydia is often asymptomatic and no association was found with a history of previous STD, vaginitis or lower abdominal pain. It is recommended that women attending antenatal, family planning and STD clinics be screened for chlamydia infection and treated, together with their sexual partners, as an effective way of prevention. Enhanced chlamydia surveillance and strengthened laboratory capabilities are also recommended. (AU)