EHP Library Environmental Health Update No. 21-October 26, 2001 

WHO has recently set up a useful website on medical wastes. A nursing group has developed as Home Hygiene Assessment Tool that may be useful for EHP activities and I have emailed the author for more info and a copy of the article.

Please send an email if you would like to receive the bi-weekly Environmental Health Updates.

A. New/Updated Websites

• CDC Website on Anthrax
• Supercouse on Epidemiology  (New online presentations on malaria epidemiology, health policy in Russia and others
• WHO Health Care Wastes Website

B. Journal Articles

• Epidemiology of rotavirus in India.
• How clean is the home environment?: a tool to assess home hygiene.
• Observation of everyday hand-washing behavior of Japanese, and effects of antibacterial soap.
• Chlorproguanil-dapsone for treatment of drug-resistant falciparum malaria in Tanzania.
• AIDS possibly caused by HIV andlatent malaria coinfection.
• An evidence-based vector control strategy for military deployments: the British Army experience.
• Repellent effects on Anopheles arabiensis biting humans in Kruger Park, South Africa.
• The efficacy of different mosquito trapping methods in a forest-fringe village, Yunnan Province, Southern China.
• Remote sensing of tropical wetlands for malaria control in Chiapas, Mexico.

Indian J Pediatr 2001 Sep;68(9):855-62

Epidemiology of rotavirus in India.

Jain V, Parashar UD, Glass RI, Bhan MK.

Viral Gastroenteritis Section, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.

Rotavirus is the leading cause of childhood diarrhea worldwide, causing an estimated 600,000 deaths each year. To assess the potential benefits of a national rotavirus immunization program in India, we analyzed 40 published studies of rotavirus that were conducted between 1976 and 1997 and included a total of approximately 13,000 Indian pediatric inpatients. Pediatric studies featuring 100 or more patients and lasting at least 12 months in duration and all neonatal studies were analyzed. Rotavirus was detected in a median of 18% of pediatric patients and 28% of neonates surveyed. Fifty percent of all children hospitalized with rotavirus by age 5 were hospitalized by the age of 6 months, 75% by the age of 9 months, and almost 100% by the age of 2 years. Rotavirus was most prevalent (31%) in children between 7 and 12 months of age, followed by children between 1 and 2 years of age (20%), and children < 7 months of age (13%). VP7 genotypes G1 and G2 were most commonly isolated although significant heterogeneity of serotypes was observed. P[11], G9 strains were most frequently isolated among neonates. In 1998; approximately 98,000 childhood deaths were caused by rotavirus. These data underscore the urgent need for safe and effective interventions against rotavirus such as vaccines. The significant diversity of rotavirus strains and young age of hospitalization pose unique challenges to the formulation of a rotavirus immunization program in India, but raise the possibility of utilizing a neonatal vaccine to provide effective coverage.

J Community Health Nurs 2001 Fall;18(3):139-50

How clean is the home environment?: a tool to assess home hygiene.

Larson EL, Gomez-Duarte C, Qureshi K, Miranda D, Kain DJ, Cablish KL.

Pharmaceutical and Therapeutic Research, Columbia University School of Nursing, 630 W. 168th Street, New York, NY 10032, USA. mailto:[email protected]

The role of the home environment in the transmission of infectious diseases has been well described in the developing world but has received less attention in developed countries. An increasing focus on home hygiene has emerged in debates regarding the use of antimicrobial products in the home and the potential for development of resistance and in discussions regarding “when is clean too clean” and “what is clean.” Studies are clearly needed to further explicate the role of the home in the spread of infectious agents, but before these can be conducted, adequate measurement tools are essential. This article describes extensive psychometric testing undertaken to develop valid and reliable methods and tools to measure home hygiene and focuses on a neighborhood that was primarily Spanish speaking in New York City. The Home Hygiene Assessment Tool described in this article can be used by clinicians and researchers to further elucidate the role of the home environment in the prevention and control of infections.

Int J Food Microbiol 2001 Aug 15;68(1-2):83-91

Observation of everyday hand-washing behavior of Japanese, and effects of antibacterial soap.

Toshima Y, Ojima M, Yamada H, Mori H, Tonomura M, Hioki Y, Koya E.

Kao Life Style Research Institute, Kao Corporation, Tokyo, Japan.
mailto:[email protected]

People wash their hands only for a short time outside the home and when preparing meals at home. This may not be sufficient for those who prepare meals because of possible secondary contamination from food. Although washing with a placebo soap for a short period (lathering 3 s and rinsing 8 s) cleansed from hands about 95% of the total coliforms transferred from ground meat, an antibacterial soap further reduced the coliform count significantly (p < 0.01). To effectively avoid secondary contamination, it is recommended that people should more frequently wash their hands, using an antibacterial soap on the areas that have been in contact with raw meat, poultry, seafood, eggs, vegetables and other foods.

Lancet 2001 Oct 13;358(9289):1218-23

Chlorproguanil-dapsone for treatment of drug-resistant falciparum malaria in Tanzania.

Mutabingwa T, Nzila A, Mberu E, Nduati E, Winstanley P, Hills E, Watkins W.

National Institute for Medical Research, Amani-Tanga, 
[email protected]

BACKGROUND: Resistance to the affordable malaria treatments chloroquine and pyrimethamine-sulfadoxine is seriously impeding malaria control through treatment in east Africa. We did an open, alternate drug allocation study to assess the efficacy of chlorproguanil-dapsone in the treatment of falciparum malaria clinically resistant to pyrimethamine-sulfadoxine. METHODS: Children younger than 5 years with non-severe falciparum malaria, attending Muheza district hospital in Tanzania, were treated with the standard regimen of pyrimethamine-sulfadoxine. Patients whose clinical symptoms resolved but who remained parasitaemic 7 days after pyrimethamine-sulfadoxine were followed up for 1 month. Clinical malaria episodes were retreated with either single dose pyrimethamine-sulfadoxine or a 3-day regimen of chlorproguanil-dapsone. Those with parasitaemia after 7 days were treated with chlorproguanil-dapsone. Parasite DNA was collected on day 7 after first treatment with pyrimethamine-sulfadoxine and we looked for point mutations in the genes encoding dihydrofolate reductase (dhfr) and dyhydropteroate synthetase (dhps). FINDINGS: 360 children were enrolled and treated with pyrimethamine-sulfadoxine. On day 7, 192 (55%) of 348 had cleared parasitaemia. Of the remaining 156 parasitaemic children, 140 (90%) were followed up to day 28, and 92 (66%) of 140 developed clinical malaria. These 92 patients were alternately retreated with either pyrimethamine-sulfadoxine (46) or chlorproguanil-dapsone (46). 28 (61%) of 46 children retreated with pyrimethamine-sulfadoxine were still parasitaemic at day 7, compared with three (15%) of 46 children retreated with chlorproguanil-dapsone. Resistance to pyrimethamine-sulfadoxine increased from 45% (156/348) at the first treatment to 61% (28/46) after retreatment. 83 of 85 parasite isolates collected after the first pyrimethamine-sulfadoxine treatment, and before and after the second treatments with pyrimethamine-sulfadoxine and chlorproguanil-dapsone showed triple-mutant dhfr alleles, associated with a variety of dhps mutations. INTERPRETATION: Most patients treated with pyrimethamine-sulfadoxine, who remain parasitaemic at day 7, develop new malaria symptoms within 1 month. Chlorproguanil-dapsone was a practicable therapy under these circumstances. Analysis of parasite dhfr and dhps before and after treatment supports the view that pyrimethamine-sulfadoxine resistance in this part of Africa is primarily due to parasites with three mutations in the dhfr domain.

Med Hypotheses 2001 Oct;57(4):419-22

AIDS possibly caused by HIV andlatent malaria coinfection.

Yaffe I. Haifa, Israel

The presented hypothesis suggests that chronic latent malaria infection prepares the niche where the otherwise feeble HIV coinfection can thrive and cause AIDS. It is suggested that the roots of the HIV outbreak and AIDS pandemic lay in the urbanization processes in Africa that resulted in the eradication of the Anopheles vector from previously endemic areas, which changed the immunological status of the inhabitants there as they lost their natural immunity to malaria. Since malarial parasites may persist in the lymphatic network for a lifetime and reduce T cell proliferation while adhering to immature dendritic cells, the loss of this natural immunity made the African population, which was chronically affected with scanty parasitemia, vulnerable to opportunistic infections, HIV among them. The specific transmission modes of latent malaria infection elucidate why AIDS flares up in Africa and spreads there evenly in the population, while in the West it expands rather slowly and is restricted mainly to homosexuals and blood recipients.

Med Trop (Mars) 2001;61(1):91-8

An evidence-based vector control strategy for military deployments: the British Army experience.

Croft AM, Baker D, von Bertele MJ.
Surgeon General’s Department, Ministry of Defence, Whitehall, London SW1A 2HB, UK.
[email protected]

We describe the British Army’s current strategy for controlling arthropod vectors of disease during overseas deployments. Military commanders and medical officers have different, but complementary responsibilities in achieving vector control. In this paper we define a hierarchy of evidence-based vector control guidelines. Field guidelines must be based on the best available research evidence, preferably that derived from pragmatic randomised controlled trials (RCTs), and from systematic reviews of trials. Assessing the effectiveness of different vector control measures involves a trade-off between the relative benefits and harm of different technology options. There is compelling scientific evidence that bed nets and screens treated with a pyrethroid insecticide are highly effective in protecting against nocturnally active, anthropophilic arthropods (including ectoparasites), and will reduce the incidence of malaria, leishmaniasis, lymphatic filariasis and Chagas’ disease. Etofenprox and deltamethrin are the safest pyrethroids, and permethrin the least safe. Vector control strategies of probable effectiveness are the use of insecticide-treated clothing, the wearing of protective clothing, and the correct use of DEET-based topical insect repellents. Aerosol insecticides are of debatable effectiveness. Other effective vector control measures, of limited usefulness during deployments, include electric fans, mosquito coils/vaporising mats, and smoke. “Biological” vector control measures, and insect buzzers/electrocuters are ineffective. Practical insect avoidance measures, based on an understanding of vector biology, complete the military vector-control arsenal. We conclude that practical insect avoidance measures, combined with pyrethroid-treated nets and clothing, and DEET-based topical repellents, can achieve almost 100% protection against biting arthropods.

Med Vet Entomol 2001 Sep;15(3):287-92

Repellent effects on Anopheles arabiensis biting humans in Kruger Park, South Africa.

Govere J, Braack LE, Durrheim DN, Hunt RH, Coetzee M.
Mpumalanga Department of Health, Nelspruit,
[email protected]

Distribution of biting sites on the human body by the malaria vector Anopheles arabiensis Patton (Diptera: Culicidae) was investigated near a source of mosquitoes in the Kruger National Park, South Africa. Eight adult male volunteers (2 teams x 2 pairs of subjects) conducted human bait collections while seated on camp chairs in the open-air, wearing only short trousers (no shirt, socks or shoes). Mosquito collections during 18.30-22.30 hours on five consecutive nights in April 1998 yielded a total of 679 An. arabiensis females biting subjects with or without their ankles and feet treated with deet insect repellent (15% diethyl-3-methylbenzamide, Tabard lotion). On subjects whose feet and ankles were smeared with repellent, 160 An. arabiensis females were captured biting in 60 manhours: 88.1% on the legs, 1.4% on the arms and 1.2% on other parts of the body, but none on the repellent-treated feet or ankles. On subjects without repellent treatment, 519 An. arabiensis were caught biting in 60 man-hours: 81.1% on feet and ankles, 16.4% on legs, 1.4% on arms and 1.2% on the rest of the body. For individual subjects, the reduction of An. arabiensis bites ranged from 36.4 to 78.2% (mean protection 69.2%). Results of this study confirm previous findings that, in this part of South Africa – inhabited only by wildlife – when people sit outside during the evening An. arabiensis prefers to bite their lower limbs: 97.5% below the knees. Overall, the number of bites by the malaria vector An. arabiensis was reduced more than three-fold (from 26 to 8/person/evening), simply by treating ankles and feet with a consumer brand of deet repellent. Whether or not this provides a satisfactory degree of protection against malaria risk would depend on the malaria sporozoite rate in the malaria vector population.

Southeast Asian J Trop Med Public Health 2001 Jun;32(2):282-9

The efficacy of different mosquito trapping methods in a forest-fringe village, Yunnan Province, Southern China.

Moore SJ, Zunwei D, Hongning Z, Xuezhong W, Hongbing L, Yujiang X, Hill N.

London School of Hygiene and Tropical Medicine, UK.

Despite a control program, malaria incidence in Yunnan has increased and knowledge of vector bionomics is needed for efficient control. Multi-drug resistant Plasmodium falciparum necessitates alternatives to human landing catches as a means of studying vectors. Therefore CDC light traps with UV or ordinary incandescent bulbs were tested for 57 trap nights. 2,703 mosquitos were caught, including the vector species An. minimus and An. sinensis and the suspected vector An. maculatus. Larval An. dirus were found around the village but no adults were trapped. UV light traps caught more mosquitos than the traps with incandescent bulbs, but caught many insects other than mosquitos requiring time-consuming separation, and were unpopular with villagers. Traps placed in living areas of houses caught more mosquitos than those placed beside bednets and the catch mainly comprised species that were active in the early evening. Encephalitis Vector Surveillance (EVS) traps hung outdoors and baited with CO2 caught few mosquitos. CDC traps in the same position baited with CO2 or lactic acid caught large numbers of Culex tritaeniorhynchus. Indoor spray catches recovered human fed An. vagus and An. minimus. This work confirmed that CDC light traps could be used to trap local vectors, and the abundance of early active mosquitos in the living area suggests that personal protection measures may be required in the evening, to supplement bed net use.

Ecol Appl 1994 Feb;4(1):81-90

Remote sensing of tropical wetlands for malaria control in Chiapas, Mexico.

Pope KO, Rejmankova E, Savage HM, Arredondo-Jimenez JI, Rodriguez MH, Roberts DR.

Geo Eco Arc Research, La Canada, California 91011, USA.

Malaria, transmitted by anopheline mosquitoes, remains a serious health problem in the tropics. Most malaria eradication efforts focus on control of anopheline vectors. These efforts include the NASA Di-Mod project, whose current goal is to integrate remote sensing, geographic information systems (GIS), and field research to predict anopheline mosquito population dynamics in the Pacific coastal plain of Chiapas, Mexico. Field studies demonstrate that high larval production of Anopheles albimanus, the principal malaria vector in the plain, can be linked to a small number of larval habitat-types, determined by larval sampling and cluster analysis of wetlands in the coastal plain. Analysis of wet and dry season Landsat Thematic Mapper (TM) satellite imagery identified 16 land cover units within an 185-km2 study area in the coastal zone. A hierarchical approach was used to link the larval habitat-types with the larger land cover units and make predictions of potential and actual low, medium, and high anopheline production. The TM-based map and GIS techniques were then used to predict differences in anopheline production at two villages, La Victoria and Efrain Gutierrez. La Victoria was predicted to have much higher Anopheles albimanus production, based upon a 2-10 times greater extent of medium- and high-producing land cover units in its vicinity. This difference between villages was independently supported by sampling (with light traps) of adults, which were 5-10 times more abundant in La Victoria.