Tropical Medicine and International Health

Objective  To determine the effect of handwashing on the risk of respiratory infection.

Methods  We searched PubMed, CAB Abstracts, Embase, Web of Science, and the Cochrane library for articles published before June 2004 in all languages. We had searched reference lists of all primary and review articles. Studies were included in the review if they reported the impact of an intervention to promote hand cleansing on respiratory infections. Studies relating to hospital‐acquired infections, long‐term care facilities, immuno‐compromised and elderly people were excluded. We independently evaluated all studies, and inclusion decisions were reached by consensus. From a primary list of 410 articles, eight interventional studies met the eligibility criteria.

Results  All eight eligible studies reported that handwashing lowered risks of respiratory infection, with risk reductions ranging from 6% to 44% [pooled value 24% (95% CI 6–40%)]. Pooling the results of only the seven homogenous studies gave a relative risk of 1.19 (95% CI 1.12%–1.26%), implying that hand cleansing can cut the risk of respiratory infection by 16% (95% CI 11–21%).

Conclusions  Handwashing is associated with lowered respiratory infection. However, studies were of poor quality, none related to developing countries, and only one to severe disease. Rigorous trials of the impact of handwashing on acute respiratory tract infection morbidity and mortality are urgently needed, especially in developing countries.

As the spread of dengue and dengue haemorrhagic fever is increasing, atypical manifestations are also on the rise, although they may be under reported because of lack of awareness. This review compiles descriptions of atypical manifestations of dengue, such as dengue encephalitis, dengue myocarditis, dengue hepatitis and dengue cholecystitis.

Objectives  To identify the gaps of knowledge and highlight the challenges and opportunities for controlling cervical cancer in sub‐Saharan Africa (SSA).

Methods  A comprehensive review of peer‐reviewed literature to summarize the epidemiological data on human papillomavirus (HPV) and invasive cervical cancer (ICC) by HIV status, to review feasible and effective cervical screening strategies, and to identify barriers in the introduction of HPV vaccination in SSA.

Results  ICC incidence in SSA is one of the highest in the world with an age‐standardized incidence rate of 31.0 per 100 000 women. The prevalence of HPV16/18, the two vaccine preventable‐types, among women with ICC, does not appear to differ by HIV status on a small case series. However, there are limited data on the role of HIV in the natural history of HPV infection in SSA. Cervical screening coverage ranges from 2.0% to 20.2% in urban areas and 0.4% to 14.0% in rural areas. There are few large scale initiatives to introduce population‐based screening using cytology, visual inspection or HPV testing. Only one vaccine safety and immunogenicity study is being conducted in Senegal and Tanzania. Few data are available on vaccine acceptability, health systems preparedness and vaccine cost‐effectiveness and long‐term impact.

Conclusions  Additional data are needed to strengthen ICC as a public health priority to introduce, implement and sustain effective cervical cancer control in Africa.

This paper summarizes and concludes in‐depth field investigations on suspected resistance of Schistosoma mansoni to praziquantel in northern Senegal. Praziquantel at 40 mg/kg usually cures 70–90% of S. mansoni infections. In an initial trial in an epidemic S. mansoni focus in northern Senegal, only 18% of the cases became parasitologically negative 12 weeks after treatment, although the reduction in mean egg counts was within normal ranges (86%). Among other hypotheses to explain the observed low cure rate in this focus, the possibility of drug resistance or tolerance had to be considered. Subsequent field trials with a shorter follow‐up period (6–8 weeks) yielded cure rates of 31–36%. Increasing the dose to 2 × 30 mg/kg did not significantly improve cure rates, whereas treatment with oxamniquine at 20 mg/kg resulted in a normal cure rate of 79%. The efficacy of praziquantel in this focus could be related to age and pre‐treatment intensity but not to other host factors, including immune profiles and water contact patterns. Treatment with praziquantel of individuals from the area residing temporarily in an urban region with no transmission, and re‐treatment after 3 weeks of non‐cured individuals within the area resulted in normal cure rates (78–88%). The application of an epidemiological model taking into account the relation between egg counts and actual worm numbers indicated that the low cure rates in this Senegalese focus could be explained by assuming a 90% worm reduction after treatment with praziquantel; in average endemic situations, such a drug efficacy would result in normal cure rates. Laboratory studies by others on the presence or absence of praziquantel resistance in Senegalese schistosome strains have so far been inconclusive. We conclude that there is no convincing evidence for praziquantel‐resistant S. mansoni in Senegal, and that the low cure rates can be attributed to high initial worm loads and intense transmission in this area.

Objective  Clinicians in resource‐poor countries need to identify patients with dengue using readily‐available data. The objective of this systematic review was to identify clinical and laboratory features that differentiate dengue fever (DF) and/or dengue haemorrhagic fever (DHF) from other febrile illnesses (OFI) in dengue–endemic populations.

Method  Systematic review of the literature from 1990 to 30 October 2007 including English publications comparing dengue and OFI.

Results  Among 49 studies reviewed, 34 did not meet our criteria for inclusion. Of the 15 studies included, 10 were prospective cohort studies and five were case–control studies. Seven studies assessed all ages, four assessed children only, and four assessed adults only. Patients with dengue had significantly lower platelet, white blood cell (WBC) and neutrophil counts, and a higher frequency of petechiae than OFI patients. Higher frequencies of myalgia, rash, haemorrhagic signs, lethargy/prostration, and arthralgia/joint pain and higher haematocrits were reported in adult patients with dengue but not in children. Most multivariable models included platelet count, WBC, rash, and signs of liver damage; however, none had high statistical validity and none considered changes in clinical features over the course of illness.

Conclusions  Several individual clinical and laboratory variables distinguish dengue from OFI; however, some variables may be dependent on age. No published multivariable model has been validated. Study design, populations, diagnostic criteria, and data collection methods differed widely across studies, and the majority of studies did not identify specific aetiologies of OFIs. More prospective studies are needed to construct a valid and generalizable algorithm to guide the differential diagnosis of dengue in endemic countries.

Intestinal schistosomiasis caused by infection with Schistosoma mansoni is a widespread public health problem in Uganda. Although long known to be endemic, its current distribution within the country requires updating of parasitological data to help guide planned control. We report such data collected between 1998 and 2002 from 201 schools and 68 communities across Uganda. In accordance with epidemiological expectation, prevalence and intensity increased with age, peaking at 10–20 years and thereafter declined moderately with age, whereas intensity declined more rapidly with age, and the prevalence of infection in a school was non‐linearly related to the mean intensity of infection. We used geographical information systems to map the distribution of infection and to overlay parasitological data with interpolated environmental surfaces. The derived maps indicate both a widespread occurrence of infection and a marked variability in infection prevalence, with prevalence typically highest near the lakeshore and along large rivers. No transmission occurred at altitudes >1400 m or where total annual rainfall was <900 mm; limits which can help estimate the population at risk of schistosomiasis. The results are discussed in reference to the ecology of infection and provide an epidemiological framework for the design and implementation of control efforts underway in Uganda.

Objectives  To develop rapid monitoring tools to detect the F1534C permethrin‐resistance mutation in domain IIIS6 of the Aedes aegypti voltage‐gated sodium channel gene and determine the frequency and distribution of this mutation in Thailand.

Methods  A TaqMan SNP genotyping and an allele specific PCR (AS‐PCR) assay were developed and validated by comparison with DNA sequencing of homozygous susceptible and homozygous resistant laboratory strains, their reciprocal‐cross progenies, and field‐caught mosquitoes. To determine the resistance phenotype of wild‐caught A. aegypti, mosquitoes were exposed to 0.75% permethrin paper. The AS‐PCR assay was used to screen 619 individuals from 20 localities throughout Thailand.

Results  Overall, both assays gave results consistent with DNA sequencing for laboratory strains of known genotype and for wild‐caught A. aegypti. The only slight discrepancy was for the AS‐PCR method, which overestimated the mutant allele frequency by 1.8% in wild‐caught samples. AS‐PCR assays of permethrin‐exposed samples show that the mutant C1534 allele is very closely associated with the resistant phenotype. However, 19 permethrin‐resistant individuals were homozygous for the wild‐type F1534 allele. DNA sequencing revealed all these individuals were homozygous for two other mutations in domain II, V1016G and S989P, which are known to confer resistance (Srisawat et al. 2010). The F1534C mutation is widespread in Thailand with mutant allele frequencies varying among populations from 0.20 to 1.00.

Conclusions  These assays can be used for the rapid detection of the F1534C resistance mutation in A. aegypti populations. The F1534C, and other, mutations underlie an extremely high prevalence of pyrethroid resistance in Thailand.

Objective  To provide data about wealth distribution in visceral leishmanisis (VL)‐affected communities compared to that of the general population of Bihar State, India.

Methods  After extensive disease risk mapping, 16 clusters with high VL transmission were selected in Bihar. An exhaustive census of all households in the clusters was conducted and socio‐economic household characteristics were documented by questionnaire. Data on the general Bihar population taken from the National Family Health Survey of India were used for comparison. An asset index was developed based on Principal Components Analysis and the distribution of this asset index for the VL communities was compared with that of the general population of Bihar.

Results  83% of households in communities with high VL attack rates belonged to the two lowest quintiles of the Bihar wealth distribution. All socio‐economic indicators showed significantly lower wealth for those households.

Conclusion  Visceral leishmanisis clearly affects the poorest of the poor in India. They are most vulnerable, as this vector‐born disease is linked to poor housing and unhealthy habitats. The disease leads the affected households to more destitution because of its impact on household income and wealth. Support for the present VL elimination initiative is important in the fight against poverty.

In rural, malaria‐endemic Burkina Faso, we evaluated the impact of the use of pre‐packaged antimalarial drugs (PPAM), by mothers in the home, on the progression of disease in children from uncomplicated fever to severe malaria. In each village of one province, a core group of opinion leaders (mainly older mothers) was trained in the management of uncomplicated malaria, including the administration of PPAM. Full courses of antimalarial (chloroquine) and antipyretic (aspirin) drugs were packaged in age‐specific bags and made widely available through community health workers who were supplied through the existing drug distribution system. Drugs were sold under a cost‐recovery scheme. Local schoolteachers conducted surveys in a random sample of 32 villages at the end of the high transmission seasons in 1998 and 1999. Disease history and the treatment received were investigated for all children under the age of 6 years having suffered from a fever episode in the previous 4 weeks. ‘Uncomplicated malaria’ was defined as every episode of fever and ‘severe malaria’ as every episode of fever followed by convulsions or loss of consciousness. During the study period, 56%[95% confidence interval (CI) 50–62%] of 3202 fever episodes in children under 6 years of age were treated promptly by mothers with the pre‐packaged drugs made available by the study. A total of 59% of children receiving PPAM were reported to have received the drugs over the prescribed 3‐day period, while 52% received the correct age‐specific dose. PPAM use was similar among literate (61%) and non‐literate mothers (55%) (P = 0.08). The overall reported risk of developing severe malaria was 8%. This risk was lower in children treated with PPAM (5%) than in children not treated with PPAM (11%) (risk ratio = 0.47; 95% CI 0.37, 0.60; P < 0.0001). This estimate of the impact of PPAM was largely unchanged when account was taken of potential confounding by age, sex, maternal literacy status, year or village. Our findings support the view that, after appropriate training and with adequately packaged drugs made available, mothers can recognize and treat promptly and correctly malarial episodes in their children and, by doing so, reduce the incidence of severe disease.

Objectives  Despite a heavy burden of HIV/AIDS and other blood borne infections, few studies have investigated needle stick injuries in sub‐Saharan Africa. We conducted a cross‐sectional study at Mulago national referral hospital in Kampala, Uganda, to assess the occurrence and risk factors of needle stick injuries among nurses and midwives.

Methods  A total of 526 nurses and midwives involved in the direct day‐to‐day management of patients answered a questionnaire inquiring about occurrence of needle stick injuries and about potential predictors, including work experience, work load, working habits, training, and risk behaviour.

Results  A 57% of the nurses and midwives had experienced at least one needle stick injury in the last year. Only 18% had not experienced any such injury in their entire career. The rate of needle stick injuries was 4.2 per person‐year. Multiple logistic regression analysis showed that the most important risk factor for needle stick injuries was lack of training on such injuries (OR 5.72, 95% CI 3.41–9.62). Other important risk factors included working for more than 40 h/week (OR 1.90, 95% CI 1.20–3.31), recapping needles most of the time (OR 1.78, 95% CI 1.11–2.86), and not using gloves when handling needles (OR 1.91, 95% CI 1.10–3.32).

Conclusions  The study showed a high rate of needle stick injuries among nurses and midwives working in Uganda. The strongest predictor for needle stick injuries was lack of training. Other important risk factors were related to long working hours, working habits, and experience.