AFRO-NETS> Environmental health update - October 26, 2001

[Dan Campbell <CampbellDB@ehproject.org>]

Environmental health update - October 26, 2001
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If you would like to receive the bi-weekly environmental health up-
date from the library of the Environmental Health Project, please 
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A. New/Updated Websites

* CDC Website on Anthrax -
  http://www.cdc.gov/ncidod/dbmd/diseaseinfo/anthrax_g.htm

* Supercourse on Epidemiology - 
  http://www.pitt.edu/~super1/main/new.htm
  (New online presentations on malaria epidemiology, health policy in
  Russia and others)

* WHO Health Care Wastes - 
  http://www.healthcarewaste.org

B. Journal Articles (abstracts below)

* 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 ef-
  fects of antibacterial soap.
* Chlorproguanil-dapsone for treatment of drug-resistant falciparum
  malaria in Tanzania.
* AIDS possibly caused by HIV and latent malaria co-infection.
* 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.


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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 Dis-
eases, National Center for Infectious Diseases, Centers for Disease 
Control and Prevention, Atlanta, Georgia, USA.

Rotavirus is the leading cause of childhood diarrhea worldwide, caus-
ing 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 be-
tween 1976 and 1997 and included a total of approximately 13,000 In-
dian 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 geno-
types G1 and G2 were most commonly isolated although significant het-
erogeneity 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 formula-
tion of a rotavirus immunization program in India, but raise the pos-
sibility of utilizing a neonatal vaccine to provide effective cover-
age.

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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:ell23@columbia.edu

The role of the home environment in the transmission of infectious 
diseases has been well described in the developing world but has re-
ceived less attention in developed countries. An increasing focus on 
home hygiene has emerged in debates regarding the use of antimicro-
bial products in the home and the potential for development of resis-
tance 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 ar-
ticle describes extensive psychometric testing undertaken to develop 
valid and reliable methods and tools to measure home hygiene and fo-
cuses 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 infec-
tions.

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Int J Food Microbiol 2001 Aug 15;68(1-2):83-91 
Observation of everyday hand-washing behavior of Japanese, and ef-
fects 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:381101@kastanet.kao.co.jp

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 (lath-
ering 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.

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Lancet 2001 Oct 13;358(9289):1218-23 
Chlorproguanil-dapsone for treatment of drug-resistant falciparum ma-
laria in Tanzania.

Mutabingwa T, Nzila A, Mberu E, Nduati E, Winstanley P, Hills E, Wat-
kins W.

National Institute for Medical Research, Amani-Tanga, Tanzania. 
mailto:tkmuta@ud.co.tz

BACKGROUND: Resistance to the affordable malaria treatments chloro-
quine 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 ma-
laria, 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. Clini-
cal 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 chil-
dren 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 in-
creased from 45% (156/348) at the first treatment to 61% (28/46) af-
ter 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 muta-
tions in the dhfr domain.


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Med Hypotheses 2001 Oct;57(4):419-22 
AIDS possibly caused by HIV and latent malaria co-infection.

Yaffe I. Haifa, Israel

The presented hypothesis suggests that chronic latent malaria infec-
tion prepares the niche where the otherwise feeble HIV co-infection 
can thrive and cause AIDS. It is suggested that the roots of the HIV 
outbreak and AIDS pandemic lay in the urbanization processes in Af-
rica 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 ho-
mosexuals and blood recipients.

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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, Min-
istry of Defence, Whitehall, London SW1A 2HB, UK. 
mailto:AshleyCroft@compuserve.com

We describe the British Army's current strategy for controlling ar-
thropod vectors of disease during overseas deployments. Military com-
manders and medical officers have different, but complementary re-
sponsibilities in achieving vector control. In this paper we define a 
hierarchy of evidence-based vector control guidelines. Field guide-
lines must be based on the best available research evidence, prefera-
bly 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 ectopara-
sites), and will reduce the incidence of malaria, leishmaniasis, lym-
phatic 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 insecti-
cide-treated clothing, the wearing of protective clothing, and the 
correct use of DEET-based topical insect repellents. Aerosol insecti-
cides 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 con-
clude that practical insect avoidance measures, combined with pyre-
throid-treated nets and clothing, and DEET-based topical repellents, 
can achieve almost 100% protection against biting arthropods.

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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 De-
partment of Health, Nelspruit, South Africa. 
mailto:JohnG@social.mpu.gov.za

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 Af-
rica. 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 re-
pellent 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 ma-
laria vector An. arabiensis was reduced more than three-fold (from 26 
to 8/person/evening), simply by treating ankles and feet with a con-
sumer brand of deet repellent. Whether or not this provides a satis-
factory degree of protection against malaria risk would depend on the 
malaria sporozoite rate in the malaria vector population.

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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 com-
prised 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. In-
door 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.

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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, geo-
graphic 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 pro-
duction of Anopheles albimanus, the principal malaria vector in the 
plain, can be linked to a small number of larval habitat-types, de-
termined 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 sup-
ported by sampling (with light traps) of adults, which were 5-10 
times more abundant in La Victoria.

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