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Diarrheal diseases have been known to cause death in many children below the age of five years, and rotavirus infection represents a major health problem in the world today, particularly in developing countries. The recent outbreak of rotavirus gastroenteritis in Samoa led to the introduction of her debut national immunization program on rotavirus vaccination for infants. Despite the introduction of anti-viral and anti-emetic drugs as of the containment approaches towards the virus, risk factors, preventive measures and public health preparedness against rotavirus infection are poorly understood in Samoa. This review aims to use available evidence on rotavirus literature to elucidate and map preventive strategies for the recently emerged rotavirus infections in Samoa. We conducted a search strategy using online medical literature databases and retrieval systems. A designated set of keywords such as rotavirus, gastroenteritis, outbreak, risk factors, containment measures, vaccination and Samoa were inserted in electronic databases to retrieve articles. The databases included PubMed, Google Scholar, MEDLINE, Scinapse, and EBSCO host. Findings from this review addressed the impact of rotavirus infection, associated threats and other preventive measures. Introducing useful health frameworks in pursuing possible methods such as improved water quality, exclusive breast feeding, improved laboratory diagnostics and outbreak surveillance, may be essential in addressing alternate approaches towards containment of the disease in Samoa and other Pacific Island Countries and Territories.
RESUMEN
Objectives@#To estimate prevalence levels of and time trends for active syphilis, gonorrhoea and chlamydia in women aged 15–49 years in four countries in the Pacific (Fiji, the Federated States of Micronesia [FSM], Papua New Guinea [PNG] and Samoa) to inform surveillance and control strategies for sexually transmitted infections (STIs).@*Methods@#The Spectrum-STI model was fitted to data from prevalence surveys and screenings of adult female populations collected during 1995−2017 and adjusted for diagnostic test performance and to account for undersampled high-risk populations. For chlamydia and gonorrhoea, data were further adjusted for age and differences between urban and rural areas.@*Results@#Prevalence levels were estimated as a percentage (95% confidence interval). In 2017, active syphilis prevalence was estimated in Fiji at 3.89% (2.82 to 5.06), in FSM at 1.48% (0.93 to 2.16), in PNG at 3.91% (1.67 to 7.24) and in Samoa at 0.16% (0.07 to 0.37). For gonorrhoea, the prevalence in Fiji was 1.63% (0.50 to 3.87); in FSM it was 1.59% (0.49 to 3.58); in PNG it was 11.0% (7.25 to 16.1); and in Samoa it was 1.61% (1.17 to 2.19). The prevalence of chlamydia in Fiji was 24.1% (16.5 to 32.7); in FSM it was 23.9% (18.5 to 30.6); in PNG it was 14.8% (7.39 to 24.7); and in Samoa it was 30.6% (26.8 to 35.0). For each specific disease within each country, the 95% confidence intervals overlapped for 2000 and 2017, although in PNG the 2017 estimates for all three STIs were below the 2000 estimates. These patterns were robust in the sen sitivity analyses.@*Discussion@#This study demonstrated a persistently high prevalence of three major bacterial STIs across four countries in WHO’s Western Pacific Region during nearly two decades. Further strengthening of strategies to control and prevent STIs is warranted.
RESUMEN
Abstract@#In Samoa, the seroprevalence rates of sexually transmitted infections other than HIV have been endemically high over the past decade, despite years of prevention programming. Odds ratio and χ2 tests were conducted to compare the rates of positivity of chlamydia, gonorrhoea, hepatitis B and C, and syphilis across age groups from 2012 and 2017 surveillance data in Samoa. Young people aged 15–19 years were significantly more likely to have a chlamydia infection compared to all other age groups in both 2012 and 2017. Hepatitis B infections were more common in males and those aged 30 and above in both 2012 and 2017. Hepatitis C had no significant differences in age, but it was more common in males in 2012 and more common in females in 2017. Older age groups (aged 45 and above) were more likely to have a positive syphilis test in both 2014 and 2017 when compared to those aged 15–24 years. The results of this analysis confirm previously observed trends in Samoa for younger age groups’ prevalence of chlamydia and gonorrhoea, and for older age groups’ prevalence of hepatitis B and C. But the analysis also unexpectedly found that older age groups (aged 45 and above) are more likely to test positive for syphilis (for years 2014 and 2017). Further studies are needed to assess behavioural risk factors associated with older populations in order to explain the increase in risk and to design interventions suited to this demographic.
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The Ministry of Health in Samoa, in partnership with the Pacific Community, successfully implemented enhanced surveillance for the high-profile Third United Nations Conference on Small Island Developing States held concurrently with the popular local Teuila festival during a widespread chikungunya outbreak in September 2014. Samoa’s weekly syndromic surveillance system was expanded to 12 syndromes and 10 sentinel sites from four syndromes and seven sentinel sites; sites included the national hospital, four private health clinics and three national health service clinics. Daily situation reports were produced and were disseminated through PacNet (the email alert and communication tool of the Pacific Public Health Surveillance Network) together with daily prioritized line lists of syndrome activity to facilitate rapid response and investigation by the Samoan EpiNet team. Standard operating procedures for surveillance and response were introduced, together with a sustainability plan, including a monitoring and evaluation framework, to facilitate the transition of the mass gathering surveillance improvements to routine surveillance. The enhanced surveillance performed well, providing vital disease early warning and health security assurance. A total of 2386 encounters and 708 syndrome cases were reported. Influenza-like illness was the most frequently seen syndrome (17%). No new infectious disease outbreaks were recorded. The experience emphasized: (1) the need for a long lead time to pilot the surveillance enhancements and to maximize their sustainability; (2) the importance of good communication between key stakeholders; and (3) having sufficient staff dedicated to both surveillance and response.
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Diethylcarbamazine (DEC), first introduced in 1947, was shown to have strong efficacy and safety for treatment of human lymphatic filariasis, which is caused mostly by a species <I>Wuchereria bancrofti.</I> Many studies to optimize the dosage and treatment schedule of DEC followed, and, based on the results, control programs with various regimens were implemented in different endemic areas⁄countries. By the mid 1970s, with endorsement by the WHO Expert Committee on Filariasis (3rd report, 1974), the standard DEC regimen for <I>W. bancrofti</I> infection in mass treatment had been established in principle: a total dose of 72 mg⁄kg of body weight given in 12 divided doses, once weekly or monthly, at 6 mg⁄kg each. Not long after the committee report, the efficacy of annual single-dose treatment at 6 mg⁄kg, which is only one twelfth of the WHO-recommended dose in a year, was reported effective in French Polynesia (study period: 1973-78), and later in Samoa (study period: 1979-81). These results were published between 1978 and 1985 in the Bulletin of WHO but received little attention. In the mid 1980s, the efficacy of ivermectin, the first-choice drug for onchocerciasis, against lymphatic filariae came to light. Since the effect at a single dose was remarkable, and often better than DEC, it was predicted that the newly introduced drug would replace DEC. Treatment experiments with ivermectin increased quickly in number. Meanwhile, annual single-dose mass drug administration (MDA) with DEC at 6 mg⁄kg was under scrutiny in Samoa and Fiji. In the early 1990s, the Samoan study, which covered the entire population of 160,000 with 3 annual MDAs, reported a significant reduction in microfilaria (mf) prevalence and mean mf density, while in Fiji, the efficacy of 5 rounds of annual MDA (total dose, 30 mg⁄kg) was shown to be as effective as 28 multi-dose MDA spread over 2 years (6 weekly plus 22 monthly treatments at 5 mg⁄kg; total dose, 140 mg⁄kg). Several additional studies carried out in Samoa in relation to the annual single-dose MDAs revealed that low density mf carriers, who have a very low mf count of 1-20⁄ml of venous blood, could not play a significant role in filariasis transmission.<br>From around 1990, studies on spaced low-dose DEC treatments and various types of combination chemotherapy with DEC and ivermectin increased. Albendazole, a well-known anti-intestinal helminths agent, was later added to the combination. The main findings of these studies with <I>W. bancrofti</I> are: (i) a single dose of DEC at 6 mg⁄kg reduced mean mf density by ca. 90% 1 year after treatment; (ii) the same dose could damage⁄kill adult worms; (iii) a single dose of ivermectin at ca. 400 μg⁄kg was more effective than DEC in reducing mf density during the first year and was similarly or less effective in the second year; (iv) ivermectin probably could not kill adult worms; (v) a single combined dose of albendazole (400 mg) and DEC (6 mg⁄kg) was effective to reduce mf density by 85 to nearly 100% 12-24 months after treatment; and (vi) ivermectin or albendazole included in the combination chemotherapy produced “beyond-filariasis” benefits: clearance⁄reduction of intestinal helminths, and, additionally, in the case of ivermectin, skin-dwelling ectoparasites.<br>The Global Programme to Eliminate Lymphatic Filariasis (GPELF) started its worldwide activities in 2000, with the target of elimination by 2020. The basic strategy is to conduct annual single-dose MDAs for 4-6 years. In 2000-2007, a minimum of 570 million individuals were treated in 48 of 83 endemic countries. The drugs used are DEC 6 mg⁄kg plus albendazole 400 mg in most countries, or ivermectin 200-400 μg⁄kg plus albendazole 400 mg particularly in onchocerciasis endemic countries in Africa. (MDAs with DEC alone had been used in India.)
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<I>Background</I><br>Samoa was formerly highly endemic for Wuchereria bancrofti filariasis transmitted by Aedes mosquitoes. Previous control efforts including sporadic mass drug administration (MDA) campaigns have reduced the prevalence to low levels but have not succeeded in eliminating the disease. To effectively plan, model and evaluate the worldwide elimination effort, the Global Programme to Eliminate Lymphatic Filariasis (GPFLF) needs data on filariasis epidemiology (including age and sex-specific prevalence and the density of microfilariae (Mf)) and estimates of the number of years of MDA required for elimination. The five-year nationwide MDA campaign carried out in Samoa before the start of the Pacific Programme to Eliminate Lymphatic Filariasis (PacELF) generated extensive data on these issues.<br><I>Methodology⁄Principal Findings</I><br>MDA campaigns were conducted in Samoa with diethylcarbamazine (DEC) in 1993 to 1995 and DEC plus ivermectin in 1996 to 1997 for all persons aged 2 years and above. Coverage of the MDA, as assessed from the campaign village register books, ranged from 62% to 97% depending on the year, and was over 80% in three out of five years. Village based surveys showed that prevalence of Mf declined from 4.3% in 1993 (N=10,256) to 1.1% in 1998 (N=4,054) (Pχ<SUP>2</SUP>=94.4, p<0.001). Males had a three- to five-fold higher prevalence than females, and this difference remained consistent over the five-year period. Transmission was still occurring over the period as shown by the occurrence of new infections in 3 children less than 5 years old out of 5,691 tested (five-year cumulative incidence of 0.53 per thousand children for the period 1993 to 1998). There was a statistically significant reduction in the geometric mean number of Mf per 60 μl in positive cases between 1993 (11.8) and 1998 (6.9) (t=2.61; p<0.01). The proportion of people with a high density of Mf - over 60 Mf per 60 μl (1000 per ml) - declined from to 19.4% to 4.0% (Pχ<SUP>2</SUP>=5.6, p=0.018).<I><br>Conclusions⁄Significance</I><br>Five years of sustained MDA with DEC (3 years) and DEC plus ivermectin (2 years) reduced the prevalence of Mf of <I>W.bancrofti</I> in Samoa by 74%. Density of Mf in infected individuals was also significantly reduced. Males had a three to five-fold higher prevalence than women. New infections in children less than five years old still occurred at a low level, suggesting that transmission was not completely interrupted. These findings helped to prepare a sound monitoring and evaluation plan for PacELF.