Tropical Medicine and International Health
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Drug‐resistance of <i>Trypanosoma b. rhodesiense</i> isolates from Tanzania Summary Objective To determine the drug resistance of Trypanosoma brucei rhodesiense strains isolated from sleeping sickness patients in Tanzania.Method We first screened 35 T. b. rhodesiense strains in the mouse model, for sensitivity to melarsoprol (1.8, 3.6 and 7.2 mg/kg), diminazene aceturate (3.5, 7 and 14 mg/kg), suramin (5, 10 and 20 mg/kg) and isometamidium (0.1, 1.0 and 2 mg/kg). A 13 isolates suspected to be resistant were selected for further testing in vitro and in vivo . From the in vitro testing, IC50 values were determined by short‐term viability assay, and MIC values were calculated by long‐term viability assay. For in vivo testing, doses higher than those in the initial screening test were used.Results Two T. b rhodesiense stocks expressed resistance in vivo to melarsoprol at 5 mg/kg and at 10 mg/kg. These strains had high IC50 and MIC values consistent with those of the melarsoprol‐resistant reference strain. Another isolate relapsed after treatment with 5 mg/kg of melarsoprol although it did not appear resistant in vitro . One isolate was resistant to diminazene at 14 mg/kg and another was resistant at both 14 and 28 mg/kg of diminazene. These two isolates had high IC50 values consistent with the diminazene‐resistant reference strain. Two isolates relapsed at a dose of 5 mg/kg of suramin, although no isolate appeared resistant in the in vitro tests. Two isolates were resistant to isometamidium at 1.0 mg/kg and had higher IC50 values. Two isolates were cross‐resistant to melarsoprol and diminazene and one isolate was cross‐resistant to suramin and isometamidium.Conclusion The reduced susceptibility of T. b. rhodesiense isolates to these drugs strongly indicates that drug resistance may be emerging in north–western Tanzania.
Tropical Medicine and International Health - Tập 11 Số 2 - Trang 144-155 - 2006
Evaluation of enrichment method for the detection of <i><scp>V</scp>ibrio cholerae </i><scp>O</scp>1 using a rapid dipstick test in <scp>B</scp>angladesh Abstract Background To evaluate the specificity of the Crystal VC dipstick test for detecting cholera. Methods We compared direct testing using the Crystal VC dipstick test and testing after enrichment for 6 h in alkaline peptone water (APW ) to bacterial culture as the gold standard. Samples positive by dipstick but negative by culture were also tested using PCR . Results Stool was collected from 125 patients. The overall specificities of the direct testing and testing after 6‐h enrichment in APW compared to bacterial culture were 91.8% and 98.4% (P = 0.125), respectively, and the sensitivities were 65.6% and 75.0% (P = 0.07), respectively. Conclusion The increase in the sensitivity of the Crystal VC kit with the use of the 6‐h enrichment step in APW compared to direct testing was marginally significant. The Crystal VC dipstick had a much higher specificity than previously reported (91–98%). Therefore, this method might be a promising screening tool for cholera outbreak surveillance in resource‐limited settings where elimination of false‐positive results is critical.
Tropical Medicine and International Health - Tập 19 Số 3 - Trang 301-307 - 2014
Patterns of treatment for malaria in Tayabas, The Philippines: Implications for control This paper describes local understandings of illness and documents treatment‐seeking behaviour in Tayabas, Quezon, The Philippines. Data were collected using focus group discussions and narrative interviews with adults, and with mothers of children, who had had confirmed malaria during a two‐month surveillance period. Signs and symptoms of malaria are important in directing individual diagnosis, treatment‐seeking and therapy. Household therapy with antimalarials, and more commonly antipyretics and herbs, as used before seeking care from either the formal or informal sector. Care outside the home was sought where symptoms continued and/or worsened, with an average period of time from onset of symptoms to presentation to a clinic of six days. Accessibility to clinics is not a problem in the study area and hence the primary reason for delay was propensity to self‐treat first and to discontinue medication when feeling better. These factors affect the control of malaria and the potential to reduce transmission. Better advice to the community regarding the importance of diagnosis and compliance with antimalarial therapy is indicated.
Tropical Medicine and International Health - Tập 3 Số 5 - Trang 413-421 - 1998
Macrofilaricidal effect of 4 weeks of treatment with doxycycline on <i>Wuchereria bancrofti</i> Summary Objective To evaluate the efficacy of doxycycline as a macrofilaricidal agent against Wuchereria bancrofti. Method In the Western Region of Ghana, 18 patients infected with W. bancrofti were recruited and treated with 200 mg doxycycline per day for 4 weeks. Seven untreated patients served as controls. Four months after doxycycline treatment, all patients received 150 μg/kg ivermectin. Patients were monitored for Wolbachia and microfilaria loads, antigenaemia and filarial dance sign (FDS).Results Four months after doxycycline treatment, cases had a significantly lower Wolbachia load than controls; and 24 months after treatment, microfilaraemia, antigenaemia and frequency of FDS were significantly lower in cases than controls. Most importantly, 4 weeks of doxycycline killed 80% of macrofilariae, which is comparable with the results of a 6‐week regimen. Circulating filarial antigenaemia and FDS were strongly correlated.Conclusion A 4‐week regimen of doxycycline seems sufficient to kill adult W. bancrofti and could be advantageous for the treatment of individual patients, e.g. in outpatient clinics.
Tropical Medicine and International Health - Tập 12 Số 12 - Trang 1433-1441 - 2007
Handwashing and risk of respiratory infections: a quantitative systematic review Summary 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.
Tropical Medicine and International Health - Tập 11 Số 3 - Trang 258-267 - 2006
Epidemiology and prevention of human papillomavirus and cervical cancer in sub‐Saharan Africa: a comprehensive review Summary 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.
Tropical Medicine and International Health - Tập 14 Số 10 - Trang 1287-1302 - 2009
Re‐emerging chikungunya fever: some lessons from Asia Summary Chikungunya is an arboviral infection that re‐emerged in several Asian countries during 2005–2006 after a long period of quiescence. Several microbial, climatic, social and economic factors influenced the occurrence of this disease as well as the rapidity with which it swept across many countries resulting in significant morbidity. Prevention and control of such diseases require not only a strong public health infrastructure but also a precise understanding of the factors that provide a conducive environment for the virus to propagate and infect a large number of people in a short time period. A multipronged response with an active role by the communities is critical for combating chikungunya and other emerging infectious diseases. The paper discusses important lessons that can be learned from the recent outbreaks of chikungunya fever in Asia.
Tropical Medicine and International Health - Tập 14 Số 8 - Trang 940-946 - 2009
Vaccine coverage with hepatitis B and other vaccines in the Colombian Amazon: do health worker knowledge and perception influence coverage? Summary Objectives We conducted a vaccination coverage survey in the Colombian Amazon, an area highly endemic for hepatitis B (HB), where HB vaccine was introduced in 1992. The aim was to measure vaccine coverage and factors influencing it, especially those related to health services.Methods A total of 3573 children younger than 11 years were randomly selected from four populations. Vaccination status was ascertained through the vaccination card and a questionnaire on socio‐demographic factors was applied to children's caretakers. Health workers (HW) in charge of vaccination in rural and urban areas were interviewed regarding knowledge and practices in vaccination. Individual and HW characteristics were related to individual vaccination using logistic regression.Results Overall cumulated vaccination coverage was high for polio (96%, 95% CI: 94–98), measles (94%, 95% CI: 92.8–95.2), BCG (91%, 95% CI: 90–93), DPT (90%, 95% CI: 88–92) and HB (88%, 95% CI: 86–90). However, <50% of children completed the primary course of vaccination in the first year of life. Individual factors improving the likelihood of being either fully or HB vaccinated were: age > 1 year, living in Leticia, being affiliated to the social security, and living in a house with a roof made of tiles rather than palm tree leaf. Among the variables related to HWs, poor knowledge of vaccine contraindications predicted a lower chance of being fully or HB vaccinated in the population served by them, even after controlling for individual variables.Conclusions The HB control program in Colombia has achieved good coverage in one of the most endemic areas of the country. However, barriers to vaccination arise from inequities in the distribution of health insurance and inadequate HW knowledge.
Tropical Medicine and International Health - Tập 10 Số 4 - Trang 322-329 - 2005
Clinical and laboratory features that distinguish dengue from other febrile illnesses in endemic populations Summary 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.
Tropical Medicine and International Health - Tập 13 Số 11 - Trang 1328-1340 - 2008
Tuberculosis disease and infection among household contacts of bacteriologically confirmed and non‐confirmed tuberculosis patients Abstract Objective To compare the prevalence of tuberculosis infection and disease in household contacts of patients with bacteriologically confirmed tuberculosis disease and contacts of non‐bacteriologically confirmed disease in western Kenya. Methods We enrolled newly diagnosed index patients and their household contacts from March 2014 to June 2016. All contacts were evaluated with a symptom questionnaire, tuberculin skin test (TST) and HIV test. Clinical evaluation and sputum testing were performed for those with symptoms, positive TST result or HIV infection. Results We enrolled 1155 contacts of 330 index patients with bacteriologically confirmed tuberculosis and 192 contacts of 55 index patients with non‐bacteriologically confirmed tuberculosis. 3.5% of contacts of patients with bacteriologically confirmed tuberculosis were diagnosed with tuberculosis, whereas no contacts of index patients with non‐bacteriologically confirmed tuberculosis were. Of those diagnosed with tuberculosis disease, 58.5% reported symptoms, 34.1% reported no symptoms but had positive TST results, and 7.3% had neither symptoms nor positive TST but were HIV‐positive. Among 872 contacts with a TST result, 50.9% of contacts of index patients with bacteriologically confirmed tuberculosis and 41.0% of contacts of index patients with non‐bacteriologically confirmed tuberculosis had a positive result (prevalence ratio = 1.16, 95% confidence interval 0.92–1.48). Conclusion In a high‐burden setting, tuberculosis disease was more prevalent among contacts of patients with bacteriologically confirmed tuberculosis than contacts of patients with non‐bacteriologically confirmed disease. TST was feasible to perform and helped to detect cases that would have been missed had only symptomatic contacts been evaluated.
Tropical Medicine and International Health - Tập 25 Số 6 - Trang 695-701 - 2020
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