Re-emerging Terror of Malaria
22 Dec, 2018
According to World Health Organization (WHO) malaria report released in November 2018, malaria decline has taken a grim U-turn in several parts of the world with re-emergence especially in Africa. Re-emerging disease is the term used for a disease which after showing a dramatic decline, again becomes a major health problem in significant proportion of the population.
Malaria cases worldwide decreased from approximately 239 million in 2010 to 217 million in 2016 but again increased to 219 million in 2017. Out of this maximum number of cases were reported from WHO African region (92% or 200 million), 5% of cases from WHO South East Asia region and 2% from Mediterranean region. Also there are mainly 5 countries which are responsible for half of all malaria cases, namely Nigeria (25%), Democratic Republic of Congo (11%), Mozambique (5%), Uganda (4%) and India (4%). Although Nigeria, Madagascar and Democratic Republic of Congo showed an increase of more than half million cases, India showed a promising decrease of 24%. Countries like Pakistan and Ethiopia also showed a downward trend. The deaths due to malaria globally in 2017 were estimated to be 435,000 as compared with 451,000 deaths in 2016. The under 5 year children accounted for 266,000 deaths in 2017. Also 93% deaths were reported from WHO Africa region. There has been decline in malaria deaths in WHO regions of America.
Malaria is caused by protozoan plasmodium. There are 5 species of plasmodium which can cause malaria in humans: plasmodium vivax, plasmodium falciparum, plasmodium ovale, plasmodium malariae and plasmodium knowlesi. The falciparum and knowlesi species are notorious to cause complicated malaria, however other species can also lead to complications. The knowledge of endemicity of particular strain of plasmodium is very important so as to start targeted treatment. It is interesting to know that morphology of plasmodium knowlesi is very similar to plasmodium malariae but as it is essentially endemic to South East Asia mainly Malaysia, one must be careful while identifying it by microscopy. Also most of these species are now being resistant to chloroquine, hence there are recommendations to start Artemisinin combination therapy (ACT) instead of monotherapy more so for plasmodium falciparum, complicated plasmodium vivax infection or plasmodium knowlesi malaria early to prevent mortality.
The cause of malaria re-emergence is attributed to drug resistance of parasite plasmodium falciparum mainly and resistance of vector mosquitoes (female anopheles) to pesticides. There is evidence of vector resistance to pyrethroid class of pesticides which were used to impregnate mosquito nets. Other classes of pesticides like carbamates, organochlorines and organophosphates are also not totally working against them.
Chemoprophylaxis coverage (seasonal malaria chemoprevention) which is an essential component of preventing malaria, using sulfadoxine-pyrimethamine is inadequate and almost 13.6 million at risk children were left behind due to lack of funds in Sub-Saharan Africa. In Mozambique, WHO has recently launched 'High burden to High impact' program to consolidate its fight against malaria. It is extremely important for travellers visiting malaria endemic areas to follow proper mosquito bite blocking measures as well as taking chemoprophylaxis.
Vector mosquito control measures including indoor residual spraying of insecticides, insecticide treated nets (ITN), mosquito repellent creams or coils and chemoprophylaxis work hand in hand as preventive measures to roll back malaria. This will require surveillance as well as adequate funding at both domestic and international levels to counter the terror of re-emerging malaria.
Sources:
• World Health Organization. World malaria report,
• Plasmodium knowlesi as a Threat to Global Public Health. doi: 10.3347/kjp.2015.53.5.575
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Author Information
Reepa Agrawal
DCH (Pediatrics)
News Date : 12/22/2018
Re-emerging Terror of Malaria
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12/22/2018