Zanzibar to Eliminate MALARIA by 2023

HEALTH:

Malaria disease kills a child every two minutes, is unheard of among many residents of the Unguja (Zanzibar Island) of whom have either never had the infection before, or not for a long time.

This is because the Island has managed to reduce its prevalence of malaria to below one percent, meaning that extremely few people, mostly travelers and migrant workers test positive for the mosquito-borne disease.

Using a variety of strategies like annual indoor/outdoor residual spraying, the revolutionary government of Zanzibar, a semi-autonomous government within Tanzania has been able to keep malaria-transmitting mosquitoes at bay.

Zanzibar is made up of a series of islands in the Indian Ocean off the coast of Tanzania, where until 2003, the transmission of malaria was more common.

Over the last two decades, however, the island has maintained malaria prevalence below one percent.

In 2020, an estimated 627,000 people died of malaria—most were young children in sub-Saharan Africa.

According to the latest World Health Organization’s (WHO) World Malaria report, there were an estimated 241 million malaria cases worldwide in 2020.

Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes.

It occurs mostly in poor tropical and subtropical areas of the world. In many of the countries affected by malaria, it is a leading cause of illness and death.

In areas with high transmission, the most vulnerable groups are young children, who have not developed immunity to malaria yet, and pregnant women, whose immunity has been decreased by pregnancy.

The mosquito-borne disease is among the five leading causes of death in children under five years, including pre-term birth complications, pneumonia, birth asphyxia, and diarrhoea.

According to the Zanzibar Malaria Elimination Programme, the island aims to eliminate malaria by 2023.

Science, in the form of mass indoor spraying; provision of insecticide-treated mosquito nets; community sensitization; coordinated international effort and investment, including early detection and treatment interventions that have quelled Plasmodium falciparum, the deadliest malaria parasite globally and the most prevalent in Africa— have all combined to deliver the miracle of low malaria transmission in Zanzibar.

Between 2005 and 2012, Zanzibar Malaria Elimination Programme (ZAMEP), deputy programme Faiza Bwanakheri Abbas explains, Zanzibar began a mass combination of interventions including the use of artemisinin-based combination therapy (ACT) for malaria treatment and indoor/outdoor residual spraying to reduce mosquito-breeding areas, insecticide-treated mosquito nets for malaria prevention, combined with community education which made a significant impact.

“In 2005, we introduced Artemisinin-based combination therapy (ACTs). A year later we introduced blanket indoor spraying followed by mass campaigns for use of bed nets.

ARTEMISININ-BASED COMBINATION THERAPY(ACT):

Noting that use of antimalarial drugs singly has failed to curtail the prevalence of malaria globally, particularly due to emergence of CQ-resistance, followed by multidrug-resistant P. falciparum.

WHO has recommended that all cases of acute uncomplicated falciparum malaria should be treated only by combining one of the artemisinin compounds with another effective erythrocytic schizontocide.

Advantages of ACT over other antimalarials are:

• Rapid clinical and parasitological cure.
• High cure rates (>95%) and low recrudescence rate.
• Absence of parasite resistance (the components prevent development of resistance to each other).
• Good tolerability profile

The ACT regimens for oral treatment of uncomplicated falciparum malaria that in use in Zanzibar.

Oral ACTs are not to be used in severe or complicated malaria, for which parenteral drugs are needed.

• Artemether-Lumefantrine

Lumefantrine is an orally active, high efficacy, long-acting erythrocytic schizontocide.

Lumefantrine is highly lipophilic; absorption starts after 2 hours of ingestion and peaks at 6-8 hours.

Lumefantrine is used only in combination with artemether, as FDC tablets. The two components protect each other from plasmodial resistance.

As such, no clinically relevant resistance has developed so far. Clinically efficacy is high achieving 95-99% cure rate, which is comparable to artesunate /Mefloquine (AS/MQ).

Artemether-lumefantrine is active even in multidrug resistant P.f. areas including Mefloquine (MQ) – resistant.

It has extensively employed in Southeast Asia and Africa.

While artemether quickly reduces parasite biomass and resolves symptoms, lumefantrine prevents recrudescence.

Gametocyte population is reduced, checking transmission.

Artemether-Lumefantrine must be administered with fatty food or milk, which markedly enhances lumefantrine (and so some extent artemether) absorption, and ensures adequate blood levels.

Failure to take it with fat rich food limits absorption and may result in recrudescence. This ACT is generally well tolerated; side effects are-headache, dizziness, sleep disturbances, abdominal pain, arthralgia, myalgia. pruritus and rash.

Artemether-Lumefantrine should not be given with drugs metabolized by CYP2D6(metoprolol, neuroleptic, tricyclic antidepressants, etc.), because Lumefantrine inhibits the isoenzyme CYP2D6.

It is contraindicated in first trimester of pregnancy and during breast-feeding.

• Artesunate-amodiaquine (AS/AQ)

Trials were conducted in Africa with AS/AQ co-formulated as FDC tablets, which produced high cure rates, and now this ACT has become the first-line therapy of uncomplicated falciparum malaria.

• Dihydroartemisinin(DHA)-Piperaquine

Piperaquine is a bisquinoline congener of chloroquine(CQ) developed in China as a high efficacy long-acting(half life 3-4 weeks).

In 1978, piperaquine replaced CQ in China, where it has been  extensively used for mass prophylaxis as well as treatment of malaria.

In clinical trials, efficacy of DHA-piperaquine fixed dose combination has been found comparable to artemether-lumefantrine or AS/AQ.

Safety profile of DHA-piperaquine is good and it is well tolerated even by children. However, dizziness, vomiting and other g.i. symptoms are common; rashes are rare.