Tropical Medicine and International Health

Objective To evaluate a new method of deriving the reproductive number for vector‐borne diseases from the early epidemic curves for vector‐borne diseases with incubations in the vectors and in the hosts.

Method We applied the model to several dengue epidemics in different climatic regions of Brazil: Brasilia, Belém, Fortaleza, Boa Vista.

Results The new method leads to higher estimates of the reproductive number than previous models.

Conclusion At present,Aedes aegyptidensities, the meeting of more compatible strains of viruses and mosquitoes, may lead to re‐emergence of urban yellow fever epidemics.

Objective  To investigate contraceptive use among HIV‐positive women in Ha long city and Cam Pha town of Quang Ninh, a Northern province of Vietnam.

Methods  Cross‐sectional questionnaire study among HIV‐positive women identified through the district HIV/AIDS register. Information on socioeconomic characteristics and contraceptive use before and after HIV diagnosis was obtained through structured questionnaires. Chi‐square testing was used to assess whether the included women differed from the target population in terms of age. Crude Odds ratios (ORs) were calculated to show the association between contraceptive use and the women’s socioeconomic characteristics. Logistic regression analyses were applied to adjust for possible confounding. The women’s contraceptive use before HIV testing and after HIV testing was described and compared by Chi‐square testing, and the association between post‐test counselling and the women’s use of condom was assessed by ORs.

Results  Of the 351 participants, 63% stated they had used contraception before HIV diagnosis and 89% stated they had used contraception after HIV diagnosis. Forty six per cent of the women had been using either the pill or an intrauterine device (IUD) before the diagnosis whereas the same applied for only 8% of the women after diagnosis. Thirty‐nine per cent stated they had been using condom before HIV diagnosis whereas 87% stated condom use after HIV diagnosis. Condom use was more common among women who had received post‐test counselling (OR 3.03, 95% CI 1.03–8.90).

Conclusions  A change of contraceptive methods from IUD and oral contraception before HIV diagnosis to condom use after HIV diagnosis was observed. The women’s use of condoms after HIV diagnosis was associated with having received post‐test counselling.

A community‐based programme for motorcycle rider education was provided for motorcyclists in all villages of 3 randomly selected subdistricts in Mae Sot District, Tak Province, northern Thailand, between January and March 1995. To determine the extent of changes in risk‐taking behaviours, we conducted an interview survey of motorcyclists in 3 villages selected by systematic sampling from the 3 intervention subdistricts and in 3 control (without intervention) villages for comparison in March 1997, 2 years after the programme. Motorcyclists in the intervention villages (69.7%) were significantly more likely to have valid licences than those in the control villages (46.5%). The proportion of motorcyclists who always or often wore helmets was significantly greater in the intervention sample (46.0%) than in the control sample (20.5%). In 1994, the annual incidence rate of motorcycle‐related injuries was slightly higher in the intervention areas than in the control areas. Following the education programme, the injury rates for 1995 and 1996 were significantly lower in the intervention than in the control population. The annual number and rate of fatal motorcycle injuries decreased after the intervention although there was no significant difference between the two populations. Motorcycle rider education may be a promising intervention for prevention of motorcycle‐related injuries in rural areas where road safety measures, particularly enforcement activities, are commonly limited.

Multimedia has become increasingly important in educational programmes in schools in all societies, and has potential value for health education. We developed a video and a comic book on the transmission and prevention of schistosomiasis for use in primary schools in endemic areas of China. The material was designed to increase children’s knowledge of schistosomiasis as an environmental disease and to encourage them to reduce their contact with unsafe water sources. To test the effectiveness of the video and booklet, a quasi‐experimental study was conducted among 1739 children in 50 primary schools in the Dongting Lake region. A self‐administered questionnaire pre‐ and post‐intervention showed a significant increase in knowledge about schistosomiasis in the intervention schools. Significantly, this change was associated with a decrease in contact with unsafe water sources, as established from water contact observations. This behavioural change suggests the value of short, targeted educational interventions to decrease risk of infection.

In Egypt an important component of the national schistosomiasis control policy is the regular screening of school children through the rural health units. In the Nile delta, a major challenge for the programme is the increasing predominance of Schistosoma mansoni, as compared to Schistosoma haematobium over the past 20 years, and the need to adjust strategies to this new reality. The action research project, growing out of an in‐depth study of schistosomiasis in two Nile delta villages, is intended to provide recommendations for schistosomiasis control to the Egyptian Ministry of Health and Population. This paper explores the practice of school‐based screening. We then describe the designing and testing of a revised screening procedure, which focuses on the collection of stool specimens to diagnose S. mansoni and which is comprehensive and gender‐sensitive. Opportunities for health education are discussed briefly, as this is necessary for an effective screening procedure and to prevent reinfection. In conclusion, we mention the need to incorporate screening and health education into an integrated control strategy.

A school‐ and chemotherapy‐based urinary schistosomiasis and intestinal helminth infection control programme was conducted in Matuga Division, Kwale District, Coast Province with teachers taking care of diagnosis, treatment and health education. More than 12 000 children in 36 primary schools were included in the 2‐year programme. Results for 20 evaluation schools are presented. Children with haematuria were treated with praziquantel (40 mg/kg) once a year. Within 2 years, the prevalence of haematuria in the schools was reduced from 28% (range 8–68%) to 11.4% (range 3–23%). More than 80% of the schoolchildren were infected with one or more intestinal helminths at baseline. After one year with levamisole mass chemotherapy, single dose (2.5 mg/kg) three times a year (once per school term), the prevalence of Ascaris infection was reduced by 83% from 18% to 3%, but there was no change in pretreatment prevalences of hookworm (57%) and Trichuris (56%) infections. In the second year of the programme, albendazole 600 mg once every six months was administered to the children in 10 randomly selected schools. This resulted in 52% and 23% reductions in prevalences of hookworm and Trichuris infections, respectively, in these schools and a reduction in mean intensity of infection of 52.8% and 50.3%, respectively.

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.

Objectives  To identify the aetiological agents of cutaneous leishmaniasis and to investigate the genetic polymorphism of Leishmania (Viannia) parasites circulating in an area with endemic cutaneous leishmaniasis (CL) in the Atlantic rainforest region of northeastern Brazil.

Methods  Leishmania spp. isolates came from three sources: (i) patients diagnosed clinically and parasitologically with CL based on primary lesions, secondary lesions, clinical recidiva, mucocutaneous leishmaniasis and scars; (ii) sentinel hamsters, sylvatic or synanthropic small rodents; and (iii) the sand fly species Lutzomyia whitmani. Isolates were characterised using monoclonal antibodies, multilocus enzyme electrophoresis (MLEE) and polymerase chain reaction‐restriction fragment length polymorphism of the internal transcribed spacer region rDNA locus.

Results  Seventy‐seven isolates were obtained and characterised. All isolates were identified as Leishmania (Viannia) braziliensis serodeme 1 based on reactivity to monoclonal antibodies. MLEE identified 10 zymodemes circulating in the study region. Most isolates were classified as zymodemes closely related to L. (V.) braziliensis, but five isolates were classified as Leishmania (Viannia) shawi. All but three of the identified zymodemes have so far been observed only in the study region. Enzootic transmission and multiclonal infection were observed.

Conclusions  Our results confirm that transmission cycle complexity and the co‐existence of two or more species in the same area can affect the level of genetic polymorphism in a natural Leishmania population. Although it is not possible to make inferences as to the modes of genetic exchange, one can speculate that some of the zymodemes specific to the region are hybrids of L. (V.) braziliensis and L. (V.) shawi.