[afro-nets] Mosquito and Malaria Control (45)

["Tom Oconnell" <tsoconnell2@yahoo.com>]

Mosquito and Malaria Control (45)
--------------------------------

Dear All, 

There exists an extensive body of correctly done, peer-reviewed research that decisively shows the effectiveness of insecticide treated bednets (ITNs) for greatly reducing the burden of malaria. Further, the vast majority of reputable studies, subjected to peer-review, call for a integrated mix of interventions, including ITNs, IRS, IPT and wide-spread use of ACTs, and have done so for several years.  Integrated malaria management has been the basis of WHO and RBM recommendations in SSA for years.

Those honestly seeking to control and eliminate malaria in SSA recognize that Africa is NOT a homogenous set of identical countries with identical disease patterns. No single intervention works in all environments. The appropriate mix of scientifically proven and locally appropriate malaria control interventions depends on the specific epidemiological setting: this varies within countries as well as between countries. See http://rbm.who.int/wmr2005/html/1-3.htm for a table showing how WHO and RBM have used evidence to help countries choose control strategies appropriate to their epidemiological needs. Infrastructure and country capacity to afford routine maintenance varies widely: many countries currently are unable to finance routine vehicle maintenance for public health centers and programs, like EPI. So affordability matters, including training costs and the costs of explaining to communities the risks of interventions.  

Spraying can not occur without the consent of community members. Those who actually work in Africa know how time-consuming and expensive it is to do such community sensitization to any new technology, even ULV spraying.

Please see the article “Socio-economic inequity in demand for insecticide-treated nets, in-door residual house spraying, larviciding and fogging in Sudan” [Malaria Journal. 2005 Dec 15;4:62]; http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16356177&query_hl=6&itool=pubmed_docsum 
See also “The scope and limitations of insecticide spraying in rural vector control programmes in the states of Karnataka and Tamil Nadu in India”, which shows how the effectiveness of spraying is reduced by cultural and environmental factors [Ecol Dis. 1982;1(4):243-55].
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed  
By the way, this has nothing to do with the use of DDT! The use of DDT for vector control, but not for agriculture, is approved by the Stockholm Convention on Persistent Organic Pollutants. DDT used for IRS, if local governmental authorities and health professionals feel it is indicated, is supported by RBM partners. See “Anopheles arabiensis and An. quadriannulatus resistance to DDT in South Africa” [Med Vet Entomol. 2003 Dec;17(4):417-22]
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=14651656 
   
USAID, the USA's CDC and the WHO, among many other respected organizations, have repeatedly stated that ITNs are an important part of a  SUITE of interventions. These include indoor residual spraying (IRS) and prophylactic anti-malarial medicines for pregnant women (IPT), as well as environmental management techniques (swap drainage) and behavior change to avoid sources of still water for breeding (e.g. used tires and open containers holding rainwater).  None, not one, of these organizations recommend the use of wide-spread aerial spraying of any type of insecticide for malaria control in SSA at this time.
The anti-malarial interventions they DO recommend are proven to work. The following articles in leading scientific journals have had to undergo stringent peer-review: i.e. the science behind the conclusions has been critically reviewed to ensure it is theoretically and methodologically correct.  
   
For evidence on ITNs:
1) The article “Malaria control--two years' use of insecticide-treated bednets compared with insecticide house spraying in KwaZulu-Natal” [S Afr Med J. 2001 Nov;91(11):978-83 ] which indicated ITNs  are superior to IRS alone.   http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11847921
2) The article “Insecticide-treated nets” [Adv Parasitol. 2006;61:77-128 ] which provides several studies to support its contention that the evidence shows ITNs to be extremely effective as well as cost-effective:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16735163&query_hl=2&itool=pubmed_docsum 
3) Concerning newer Long-lasting ITNs, see “Evaluation of long-lasting insecticidal nets after 2 years of household use” [Trop Med Int Health. 2005 Nov;10(11):1141-50] 
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=16262739 
   
For evidence on IRS:
1) The article “A steep decline of malaria morbidity and mortality trends in Eritrea between 2000 and 2004: the effect of combination of control methods” [Malaria J. 2006 Apr 24;5:33] which provides clear evidence that ITNs plus IRS was responsible for the dramatic reduction of malaria in Eritrea from 2000 to 2004.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16635265&query_hl=2&itool=pubmed_docsum 
2) The article “Impact of different strategies to control Plasmodium infection and anaemia on the island of Bioko (Equatorial Guinea); which states “IRS and ITNs have proven to be effective control strategies on the island of Bioko. The choice of one or other strategy is, above all, a question of operational feasibility and availability of local resources” 
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16460558&query_hl=6&itool=pubmed_docsum 
   
For evidence on IPT please see
1) “Effectiveness of intermittent preventive treatment with sulphadoxine-pyrimethamine for control of malaria in pregnancy in western Kenya: a hospital-based study”, showing confirms that IPT with SP is effective in reducing placental malaria and Low Birth Weight  [Trop Med Int Health. 2004 Mar;9(3):351-60]
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=149963642) “Prevention of anaemia in pregnancy using insecticide-treated bednets and sulfadoxine-pyrimethamine in a highly malarious area of Kenya: a randomized controlled trial” which showed that ITNs plus IPT was most successful [Trans R Soc Trop Med Hyg. 2003 May-Jun;97(3):277-82].
   
For environmental management see:
1) “Reducing the burden of malaria in different eco-epidemiological settings with environmental management: a systematic review” [Lancet Infect Dis. 2005 Nov;5(11):695-708]
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed 
2) “Engineering and malaria control: learning from the past 100 years” [Acta Trop. 2004 Jan;89(2):99-108]
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=14732233 

Finally, new Artemisinin-based Combination Therapies (ACTs) medicines are a proven and cost-effective intervention, and should be combined with ITNs, IPT and IRS. See  “Cost effectiveness analysis of strategies to combat malaria in developing countries [BMJ. 2005 Dec 3;331(7528):1299. Epub 2005 Nov 10] 
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16282381&query_hl=2&itool=pubmed_docsum 
   
These interventions work. No similar articles have appeared in any of the dozens of top-tier scientific magazines showing any evidence that wide-spread spraying, regardless of insecticide used, as any proven role in malaria control efforts.
   
The constraint to global malaria control is that developed countries have not lived up to their written commitments to fully fund the GFATM and provide developing countries the means to greatly scale up use of these proven and effective interventions.
   
Best regards,
Tom O’Connell
Consultant, health policy and planning
mailto:tsoconnell2@yahoo.com