Epidemiology and Control of Plasmodium vivax in Afghanistan

Abstract

Around half of the population of Afghanistan resides in areas at risk of malaria transmission. Two species of malaria (Plasmodium vivax and Plasmodium falciparum) account for a high burden of disease—in 2011, there were more than 300,000 confirmed cases. Around 80–95% of malaria is P. vivax. Transmission is seasonal and focal, below 2,000 m in altitude, and in irrigated areas which allow breeding of anopheline mosquito vectors. Malaria risk is stratified to improve targeting of interventions. Sixty-three of 400 districts account for ∼85% of cases, and are the target of more intense control efforts. Pressure on the disease is maintained through case management, surveillance, and use of long-lasting insecticide-treated nets. Plasmodium vivax treatment is hampered by the inability to safely treat latent hypnozoites with primaquine because G6PD deficiency affects up to 10% of males in some ethnic groups. The risk of vivax malaria recurrence (which may be as a result of reinfection or relapse) is around 30–45% in groups not treated with primaquine but 3–20% in those given 14-day or 8-week courses of primaquine. Greater access to G6PD testing and radical treatment would reduce the number of incident cases, reduce the infectious reservoir in the population, and has the potential to reduce transmission as a result. Alongside the lack of G6PD testing, under-resourcing and poor security hamper the control of malaria. Recent gains in reducing the burden of disease are fragile and at risk of reversal if pressure on the disease is not maintained.

Chloroquine–Primaquine versus Chloroquine Alone to Treat Vivax Malaria in Afghanistan: An Open Randomized Superiority Trial

“…The overall recurrence rates in the two arms are broadly similar to those previously found in Afghan refugees in Pakistan. 2 …”

“…Malaria remains a significant problem in Afghanistan where cases are caused by Plasmodium vivax . 1 , 2 Limited resources and security challenges hamper control efforts. 2 Control of vivax malaria is particularly challenging because the dormant liver stages cause multiple relapses providing a source for new transmission.…”

“… 1 , 2 Limited resources and security challenges hamper control efforts. 2 Control of vivax malaria is particularly challenging because the dormant liver stages cause multiple relapses providing a source for new transmission. 3 Trials of primaquine (PQ), the only widely available radical therapy, in Afghan refugees living in Pakistan documented good efficacy for PQ 0.25 or 0.5 mg/kg/day given over 14 days 4 , 5 or 0.75 mg/kg/week for 8 weeks, 5 compared with a 5-day PQ regimen.…”

Cost-effectiveness of adding indoor residual spraying to case management in Afghan refugee settlements in Northwest Pakistan during a prolonged malaria epidemic

“…Parts of Afghanistan and former North-West Frontier Province (NWFP), now Khyber-Pakhtunkhwa Province, Pakistan remain malaria endemic [ 11 – 14 ]. Breakdown of control infrastructure during decades of conflict led to a high annual malaria burden for Afghanistan during 1990–2010 [ 8 , 13 , 15 ]. Inflows of over 3 million Afghan refugees to Pakistan in the 1980s and 1990s led to increased transmission in newly-settled areas [ 16 – 19 ].…”

Description of Haematological Trend of Vivax Malaria Treated With Chloroquine and Primaquine in Eastern Afghanistan Laghman Province.

“…In Afghanistan, chloroquine remains first-line treatment for the erythrocyte stage of P. vivax infection, with no evidence of resistance, although it provides a shorter period of post-treatment prophylaxis than DHA-primaquine in a previous comparative trial (10). Limited resources and security challenges hamper malaria control efforts (11), In order to quantify the risks and benefits of P. vivax current treatment, it is crucial to determine the normal hematological response following P. vivax infection and treatment. The Complete Blood Count (CBC) assesses the cellular elements of the blood, that is, red cells, white cells, and platelets, both qualitatively and quantitatively (12) and is an essential tool in assessing hematological changes.…”