Towards a risk map of malaria for Sri Lanka: the importance of house location relative to vector breeding sites

BACKGROUND: In Sri Lanka, the major malaria vector Anopheles culicifacies breeds in pools formed in streams and river beds and it is likely that people living close to such breeding sites are at higher risk of malaria than people living further away. This study was done to quantify the importance of house location relative to vector breeding sites for the occurrence of malaria in order to assess the usefulness of this parameter in future malaria risk maps. Such risk maps could be important tools for planning efficient malaria control measures. METHODS: In a group of seven villages in north central Sri Lanka, malaria cases were compared with community controls for distance from house to breeding sites and a number of other variables, including type of housing construction and use of anti-mosquito measures. The presence of An. culicifacies in bedrooms was determined by indoor insecticide spray collections. RESULTS: People living within 750 m of the local stream, which was the established vector-breeding site, were at much higher risk for malaria than people living further away (odds ratio adjusted for confounding by other variables 5.93, 95% CI: 3.50-8.91). Houses close to the stream also had more adult An. culicifacies in the bedrooms. Poor housing construction was an independent risk factor for malaria. CONCLUSIONS: Risk maps of malaria in Sri Lanka can be based on the location of houses relative to streams and rivers that are potential breeding sites for the malaria vector An. culicifacies. A distance of 750 m is suggested as the cut-off point in defining low- and high-risk villages.     

Reducing acute poisoning in developing countries--options for restricting the availability of pesticides

Hundreds of thousands of people are dying around the world each year from the effects of the use, or misuse, of pesticides. This paper reviews the different options to reduce availability of the most hazardous chemicals, focusing on issues in developing countries. Emphasis is placed on the fatal poisoning cases and hence the focus on self-harm cases. Overall, it is argued here that restricting access to the most hazardous pesticides would be of paramount importance to reduce the number of severe acute poisoning cases and case-fatalities and would provide greater opportunities for preventive programmes to act effectively. The aim should be to achieve an almost immediate phasing out of the WHO Classes I and II pesticides through national policies and enforcement. These short-term aims will have to be supported by medium- and long-term objectives focusing on the substitution of pesticides with safe and cost-effective alternatives, possibly guided by the establishment of a Minimum Pesticide List, and the development of future agricultural practices where pesticide usage is reduced to an absolute minimum. Underlying factors that make individuals at risk for self-harm include domestic problems, alcohol or drug addiction, emotional distress, depression, physical illness, social isolation or financial hardship. These should be addressed through preventive health programmes and community development efforts.     

A synthetic pentasaccharide for the prevention of deep-vein thrombosis after total hip replacement

BACKGROUND: Venous thromboembolism is a frequent complication of total hip replacement. The pentasaccharide Org31540/SR90107A, a highly selective, indirect inhibitor of activated factor X, is the first of a new class of synthetic antithrombotic agents. To determine the optimal dose for phase 3 studies, we conducted a dose-ranging study in which Org31540/SR90107A was compared with a low-molecular-weight heparin, enoxaparin, in patients undergoing total hip replacement. METHODS: In a double-blind study, patients were randomly assigned to postoperative administration of one of five daily doses of Org31540/SR90107A, given once daily, or to 30 mg of enoxaparin, given every 12 hours. Treatment was continued for 10 days or until bilateral venography was performed after a minimum of 5 days. RESULTS: Of 933 patients treated, 593 were eligible for the efficacy analysis. With Org31540/SR90107A a dose effect was observed (P=0.002), with rates of venous thromboembolism of 11.8 percent, 6.7 percent, 1.7 percent, 4.4 percent, and 0 percent for the groups assigned to 0.75 mg, 1.5 mg, 3.0 mg, 6.0 mg, and 8.0 mg of the drug, respectively, as compared with a rate of 9.4 percent in the enoxaparin group. The reduction in the risk of venous thromboembolism was 82 percent for the 3.0-mg Org31540/SR90107A group (P=0.01) and 29 percent for the 1.5-mg group (P=0.51). Enrollment in the 6.0-mg and 8.0-mg Org31540/SR90107A groups was discontinued because of bleeding complications. Major bleeding occurred 3.5 percent less frequently in the 0.75-mg group (P=0.01) and 3.0 percent less frequently in the 1.5-mg group (P=0.05) than in the enoxaparin group (in which the rate was similar to that in the 3.0-mg group). CONCLUSIONS: A synthetic pentasaccharide, Org31540/SR90107A, has the potential to improve significantly the risk-benefit ratio for the prevention of venous thromboembolism, as compared with low-molecular-weight heparin.     

The association between air pollution and heart failure, arrhythmia, embolism, thrombosis, and other cardiovascular causes of death in a time series study

In a time series study, air pollution was associated with specific cardiovascular causes of death. Deaths due to heart failure (ICD-9 428), arrhythmia (ICD-9 427), cerebrovascular causes (ICD-9 430-436), and thrombocytic causes (ICD-9 415.1, 433-4, 444, 452-3) were more strongly associated with air pollution than cardiovascular deaths (ICD-9 390-448) in general. Excess relative risks were 2.5 to 4 times larger for these categories than for total cardiovascular disease mortality. Heart failure deaths, which made up 10% of all cardiovascular deaths, were found to be responsible for about 30% of the cardiovascular deaths related to particulate matter, SO2, CO, and NO2.     

Routine diagnostic procedures for chronic encephalopathy induced by solvents: survey of experts

OBJECTIVES—To study the routine diagnostic procedures used in different countries for chronic toxic encephalopathy (CTE) induced by solvents.
METHODS—By means of a postal questionnaire selected international experts were asked about the methods they use to diagnose patients suspected of having CTE induced by solvents, the number of patients, entrance criteria, and the results of these diagnostic procedures.
RESULTS—18 Experts working in 18 diagnostic centres responded. Most of them agreed that a diagnostic procedure for CTE induced by solvents should contain an interview and neurological, physical, and neuropsychological examinations. However, the tests used were very different, as were the classifications for CTE. Depending on the institute, a diagnosis of CTE was made in 6%-70% of the referred patients. The proportion of patients with CTE stage I ranged from 0% to 33%, stage II from 5% to 100%, and stage III from 0% to 95%.
CONCLUSION—The intentions of the two 1985 conferences that aimed at clarity and uniformity of diagnosis of CTE induced by solvents are far from reached. It is possible, now the conditions are more favourable, to aim at this important goal and recommend some refinement of the then proposed criteria.


     

Solvent-induced chronic encephalopathy; the 'solvent team' project

Long-term exposure to organic solvents can result in damage of the central nervous system. The WHO recognises the following stages: organic affective syndrome, mild chronic toxic encephalopathy (CTE), and severe CTE. There is no golden standard for the diagnosis of CTE. Mild CTE is characterised by fatigue, mood disturbances, memory and attention disorders. In the Netherlands, a so-called 'solvent team' consisting of an occupational physician, a neurologist, a neuropsychologist and an occupational hygienist, assesses patients suspected of having CTE. The diagnostic procedure consists of three steps: (a) interview and blood tests, (b) the computer-based Neurobehavioral Evaluation System, and (c) assessment of an exposure index, neuropsychological investigation, and clinical neurological examination. In the period 1997-1999 approximately 250 patients were assessed yearly in the Netherlands; resulting in 50 diagnoses of mild CTE a year. The real incidence is most likely higher at present, but will decline due to diminished exposure to organic solvents.     

Decreasing STD incidence and increasing condom use among Chinese sex workers following a short term intervention: a prospective cohort study

OBJECTIVE: To describe the impact of a repeating behavioural intervention focused on preventive education and provision of STD testing and treatment services to female sex workers. METHODS: A prospective cohort study of 966 sex workers (first of its kind in China) was conducted in Guangzhou from March 1998 to October 1999. At each visit information was collected on sexual behaviour, condom use and knowledge about HIV transmission and condom use, education was given, STD were diagnosed, and treatment was provided free of charge. We evaluated trends in condom use, knowledge about HIV transmission and condom use, and STD incidences. Generalised estimating equations were applied to control for repeated measurements. RESULTS: The proportion of consistent condom use increased from the intake through the third follow up visit (from 30% to 81%), as well as the proportion of having good knowledge on HIV transmission (4.3% to 98.6%) and condom use (23.6% to 79.3%). The incidence of gonorrhoea, trichomoniasis, and chlamydia decreased over each follow up visit; from 17.5/100 person years (PY), 22.4/100PY, 65.9/100PY at the first follow up visit to 5.1/100PY, 3.0/100PY, 16.1/100PY at the third follow up visit, for each STD respectively. CONCLUSIONS: STD care and prevention programmes targeting sex workers are feasible in China and, more importantly, intervention consisting of prevention education and STD care is likely to reduce unprotected sexual behaviour and STD incidence in this group at high risk for HIV and other STD infection.     

Cervical HPV infection among HIV-infected prostitutes addicted to hard drugs

An investigation into the prevalence of human papilloma virus (HPV) infection, abnormal cervical cytology and the relationship between HIV-and HPV infection was done in a group of intravenously (IV) and non-IV drug-using prostitutes. From July 1991 through May 1992, hard drugaddicted prostitutes attending a sexually-transmitted-disease (STD) clinic in Amsterdam were recruited. A questionnaire was administered to obtain demographic characteristics, and medical and STD history. Apart from routine STD examination, cervical scrapes for cytology and samples for HPV DNA detection by polymerase chain reaction (PCR) were collected. Some of the women included in this study also participated in HIV studies among drug users. Their data on HIV- and immunologic status could be combined. A total of 121 women entered the study; 25 women were HIV-seropositive, 44 women were HIV-negative, and the HIV status of 52 women was unknown. All 25 HIV-positive women had normal Pap smears, two of the 44 HIV-negative women had a Pap smear III A, and in the HIV-unknown group, two women with Pap III A and one with Pap III B were found. Eight of the 25 (32%) HIV-positive women were HPV DNA-positive, three of the 44 (7%) HIV-negative women and 10/52 (19%) of the HIV-unknown group. Logistic regression analysis showed that in the total group, presence or cervical HPV DNA was associated with HIV infection (order ratio [OR] for HIV-positives 7.8, 95% confidence interval [CI] 1.8 to 34.6) and with diagnosis of condylomata acuminata at entry to the study (OR 7.5, 95% CI 1.5 to 36.5). The mean of the calculated minimal duration of HIV infection was 6.5 years for HPV-positive women vs. 4.2 years for the HPV-negative women (P = 0.001, OR 1.8 per year, 95% CI 1.1 to 3.2). The difference of CD4 T-cell counts between HPV-positive and negative women (all HIV-positive) was statistically not significant (557/mm³ vs. 486/mm³). Our data indicate that in this group of hard drug-addicted prostitutes, HIV infection is associated with a higher prevalence of HPV infection but not with a higher rate of abnormal cervical cytology. In the group of HIV-infected women, an association between CD4 T-cell counts and HPV infection was not established.