Identification and control of an isolated, but intense focus of lymphatic filariasis on Satawal Island, Federated States of Micronesia, in 2003.

BACKGROUND: There is very limited data available on the prevalence of Bancroftian filariasis in the Federated States of Micronesia (FSM). Considerable attempts to eliminate the disease had occurred in the Pacific region by the year 2003, and the prevalence in FSM was thought to be sufficiently low that the region was considered non-endemic. However, a survey conducted in 2003 on an isolated atoll of FSM, Satawal Island, challenged that assumption. METHODS: Participants on Satawal Island were recruited and their blood tested for Wuchereria bancrofti antigen by the filariasis immunochromatographic test (ICT) card and circulating microfilaria by Knott's concentration technique. A survey for active cases of lymphoedema, elephantiasis and hydrocoele was performed and mosquitoes were trapped and dissected to detect larvae of W. bancrofti. RESULTS: A total of 104 males and 149 females from early teens to mid-80s were tested. Men had a significantly higher prevalence of infection than women in both the ICT test (53 vs 28%; p < 0.001) and by Knott's concentration results (37 vs 11%; p < 0.001). Microfilaria prevalence was higher in subjects ≤25 than in those >25 years of age. All persons sampled were treated for LF. No cases of elephantiasis or hydrocoele were detected. No Aedes dissected were positive but three of nine culicine mosquitoes were positive for L1-3 larval stages of W. bancrofti by microscopy. In depth interviews were conducted with residents and chiefs. CONCLUSIONS: This survey showed that even in regions thought to be close to elimination, isolated high intensity foci of lymphatic filariasis may occur. These need to be recognized and control measures instituted such as local MDA as in the current study.

Impact of routine hepatitis B immunization on the prevalence of chronic hepatitis B virus infection in the marshall islands and the federated States of micronesia.

BACKGROUND: To evaluate the impact of routine hepatitis B (HB) vaccination on the prevalence of chronic hepatitis B virus (HBV) infection among children in Pacific Island countries where HBV infection was highly endemic, we conducted HB serosurveys during 2000 to 2007 among women of childbearing age born before implementation of HB vaccination and among children born after its implementation. METHODS: Serum specimens were collected from children aged 2 to 6 years and their mothers in Chuuk, Federated States of Micronesia in 2000, children aged 2 to 9 years and their mothers in Pohnpei, Federated States of Micronesia in 2005, and 5- to 9-year-old children and prenatal clinic patients in 2007 in Republic of the Marshall Islands (RMI). Specimens were tested for HB surface antigen (HBsAg) and antibodies to HB core antigen (total anti-HBc). HB vaccination coverage was determined from health department vaccination registries. We defined chronic HBV infection as the presence of HBsAg. RESULTS: Birthdose and 3 dose HB vaccination coverage was 48% and 87%, respectively, in Chuuk, 87% and 90% in Pohnpei, and 49% and 93% in RMI. Chronic HBV infection prevalence among children was 2.5% (9/362) in Chuuk, 1.5% (7/478) in Pohnpei and 1.8% (6/331) in RMI. Chronic HBV infection prevalence among women was 9.2% (21/229) in Chuuk, 4.4% (10/229) in Pohnpei, and 9.5% (11/116) in RMI. CONCLUSIONS: Hepatitis B vaccination has resulted in a substantial decline in chronic infection in children in the Pacific Islands. HB vaccine effectiveness is high in this region, despite challenges in providing HB vaccine at birth and completing vaccination series on schedule.

Vaccination coverage in the US Commonwealth of the Northern Mariana Islands, 2005.

BACKGROUND: In July 2005, a house-to-house survey was conducted to determine vaccination coverage achieved through routine health services on the three inhabited islands (Saipan, Rota, and Tinian) of the US Commonwealth of the Northern Mariana Islands (CNMI). METHODS: A population-based cluster survey was conducted on Saipan; clusters and households were selected by systematic random sampling. On the smaller islands of Rota and Tinian, all households were visited. Vaccination histories and demographic information were obtained during household interview for all children aged 19-35 months, children aged 6 years, and adults aged 65 years and older. Vaccination histories for children were supplemented by hospital/clinic records and an electronic vaccination registry. RESULTS: Among 295 children aged 19-35 months, estimated coverage with the primary vaccination series was 80 percent; coverage with individual vaccines was generally higher. Among 193 children aged 6 years, coverage for vaccines required at school-aged was 83 percent. Among 226 adults aged 65 years and older, 52 percent received influenza vaccine during the previous season while 21 percent had ever received pneumococcal vaccine. CONCLUSIONS: The CNMI has achieved the US Healthy People 2010 objective of 80 percent coverage for the standard vaccination series among children aged 19-35 months. High coverage levels among 6-year-old children may reflect the benefit of school entry requirements. Influenza and pneumococcal vaccination among older adults remains low. Efforts to ensure that children and older adults throughout the CNMI are equally well-protected should continue. Strategies to address parental awareness of vaccinations that are due should be explored and may be facilitated by upgrading the electronic vaccination registry.

Can oral cholera vaccination play a role in controlling a cholera outbreak?

Control measures to limit the spread of a cholera outbreak in Pohnpei Island (Micronesia), included mass vaccination with the single-dose live-attenuated oral cholera vaccine CVD 103-HgR as a potential adjunct measure. The outbreak provided a unique opportunity to evaluate the practicality of use and effectiveness of this vaccine. Under field conditions encountered in Pohnpei, crude vaccine efficacy was estimated at 79.2% (95% CI: 71.9-84.6%) in the target population. Retrospective analysis suggests that mass vaccination with oral cholera vaccines can be a useful adjunct tool for controlling outbreaks, particularly if implemented early in association with other standard control measures.