Mutant Plasmodium falciparum chloroquine resistance transporter in Hodeidah, Yemen: association with parasitologic indices and treatment-seeking behaviors

Changes in drug demand when a pandemic coincides with other outbreaks in a war zone country: a cross-sectional pilot study

BACKGROUND

Yemen's health system has severely deteriorated due to the ongoing civil war accompanied by the COVID-19 pandemic which coincided with other outbreaks of endemic infections. Many health institutions closed due to insufficient equipment and supplies. Consequently, pharmacists became the available healthcare provider on the frontlines. This study aimed to evaluate the pattern of demand for prescription and nonprescription drugs during the pandemic based on the pharmacist's perspective in Yemen, a conflict zone country.

METHODS

An online survey was developed, validated, and distributed among pharmacists. The questionnaire was composed of two sections: (1) demographic characteristics of the participants and (2) changes in the demand for different drug categories. Chi-square test and Fisher's exact test were used to find statistical associations.

RESULTS

Responses (330) were received from pharmacists working in 12 out of 22 governorates in Yemen. During the pandemic, there was an increase in the demand for prescription drugs such as antibiotics, antimalarials, and sedatives (95%, 90%, and 71%, respectively) and an increase in the demand for nonprescription drugs such as vitamins (93%) and paracetamol (> 90%). Some of these drugs could have serious side effects if taken without medical advice, and others could result in severe effects if taken concomitantly. In addition, there was an increase in the demand for prescription drugs without a prescription, which was reported by 50% of the participants. No statistical difference was seen between the frontline districts and major cities in terms of requesting these drugs without a prescription. On the other hand, most participants (75.2%) did not attend any training or workshop during the last 6 months of conducting this survey.

CONCLUSION

COVID-19 has increased the demand for many prescription and nonprescription drugs, where the irrational use of these drugs may lead to devastating health effects. In war zone areas hit by a pandemic, policymakers and public health organizations should focus on training and educating pharmacists as important health care and medicine providers for the public.

Molecular markers associated with resistance to commonly used antimalarial drugs among Plasmodium falciparum isolates from a malaria-endemic area in Taiz governorate-Yemen during the transmission season

Since 2005, artesunate (AS) plus sulfadoxine/pyrimethamine (SP) combination has been adopted as the first-line treatment for uncomplicated malaria in Yemen in response to the high level of Plasmodium falciparum resistance to chloroquine (CQ). Therefore, the aim of the present study was to determine the frequency distribution of molecular markers associated with resistance to CQ and AS plus SP combination among P. falciparum isolates from a malaria-endemic area in Taiz governorate, Yemen. Fifty P. falciparum isolates were collected during a cross-sectional study in Mawza district, Taiz, in the period from October 2013 to April 2014. The isolates were investigated for drug resistance-associated molecular markers in five genes, including P. falciparum CQ resistance transporter (pfcrt) 76T and P. falciparum multidrug resistance 1 (pfmdr1) 86Y as markers of resistance to CQ, mutations in the Kelch 13 (K13) propeller domain for resistance to AS, and P. falciparum dihydrofolate reductase (pfdhfr) and P. falciparum dihydropteroate synthase (pfdhps) genes for resistance to SP. Nested polymerase chain reaction was used to amplify target genes in DNA extracts of the isolates followed by restriction fragment length polymorphism for detecting 76T and 86Y mutations in pfcrt and pfmdr1, respectively, and by DNA sequencing for detecting mutations in K13, pfdhfr and pfdhps. All the investigated isolates from Mawza district were harboring the pfcrt 76T mutant and the pfmdr1 N86 wild-type alleles. The pfdhfr 51I/108N double mutant allele was found in 2.2% (1/45) of the isolates; however, no mutations were detected at codons 436, 437, 540, 581 and 613 of pfdhps. All P. falciparum isolates that were successfully sequenced (n=47) showed the K13 Y493, R539, I543 and C580 wild-type alleles. In conclusion, the pfcrt 76T mutant allele is fixed in the study area about six years after the official withdrawal of CQ, possibly indicating its over-the-counter availability and continued use as a self-medication in the study area. However, the almost predominant wild-type alleles of the genes associated with resistance to AS and SP among P. falciparum isolates in the present study indicates the sustained efficacy of the currently adopted first-line treatment of AS plus SP in the study area.

High efficacy of two artemisinin-based combinations: artesunate + sulfadoxine-pyrimethamine and artemether-lumefantrine for falciparum malaria in Yemen

BACKGROUND

Artesunate + sulfadoxine-pyrimethamine (AS + SP) has been the first-line treatment and artemether-lumefantrine (AL) the second-line treatment for uncomplicated falciparum malaria in Yemen since 2005. This paper reports the results of studies conducted to monitor therapeutic efficacy of these two drugs in sentinel sites in Yemen.

METHODS

Eight therapeutic efficacy studies were conducted in six sentinel sites during the period 2009-2013 in Yemen. Five studies were for the evaluation of AS + SP (total of 465 patients) and three studies (total of 268 patients) for the evaluation of AL. The studies were done according to standard WHO protocol 2009 with 28-day follow-up.

RESULTS

In the evaluation of AS + SP, the PCR-corrected cure rate was 98 % (95 % CI 92.2-99.5 %) in one site and 100 % in all of the other four sites. In the sites where AL was evaluated, the PCR-corrected cure rate was 100 % in all the sites. All patients were negative for asexual parasitaemia on day 3 in both the AS + SP and the AL groups. There was a higher rate of clearance of gametocytaemia in the AL-treated group when compared with the AS + SP groups from day 7 onwards.

CONCLUSION

AS + SP remains the effective drug for uncomplicated falciparum malaria in Yemen. AL is also highly effective and can be an appropriate alternative to AS + SP for the treatment of falciparum malaria. AL demonstrated a higher efficacy in clearing microscopic gametocytaemia than AS + SP.

TRIAL REGISTRATION

Trial registration number ACTRN12610000696099.

Survey of chloroquine-resistant mutations in the Plasmodium falciparum pfcrt and pfmdr-1 genes in Hadhramout, Yemen

Malaria is still a major public health problem in Yemen. More than 95% of the malaria cases are due to Plasmodium ‎falciparum‎. Recently in Yemen, the antimalarial treatment policy was changed from chloroquine (CQ) to artemisinin combination therapy (ACTs). However, CQ is still available and prescribed in the Yemeni market. The persistence of CQ resistance will be prolonged if the shift to ACT and the simultaneous withdrawal of CQ are not rigorously implemented. The aim of the current survey is to detect chloroquine-resistant mutations in P. falciparum chloroquine-resistance transporter (pfcrt) and P. falciparum multi-drug resistance-1 (pfmdr1) genes. These data will be important for future monitoring and assessment of antimalarial drug policy in Yemen. Blood specimens were collected from 735 individuals from different districts of the Hadhramout province, Yemen by house-to-house visit. Mutation-specific nested polymerase chain reaction (PCR) and restriction fragment length polymorphism (PCR-RFLP) methods were used to investigate the mutations in the pfmdr1(codons 86 and 1246) and pfcrt (codons 76, 271, 326, 356 and 371) genes. The overall prevalence of pfcrt mutations at codons 76, 271, 326 and 371 were 50.4%, 58.7%, 54.3% and 44.9%, respectively. All isolates had wild-type pfcrt 356 allele. The majority of pfmdr1 86 alleles (83.3%) and all pfmdr1 1246 alleles were wild type. There was no association between pfcrt mutations and symptomatology, gender and age groups. In conclusion, point mutations in codons 76, 271, 326 and 371 of pfcrt of P. falciparum are high suggesting a sustained high CQ resistance even after 4 years of shifting to ACTs. These findings warrant complete withdrawal of CQ use from the Yemeni market for P. falciparum and careful usage of CQ for treating Plasmodium vivax.

Prevailing Plasmodium falciparum dihydrofolate reductase 108-asparagine in Hodeidah, Yemen: a questionable sulfadoxine-pyrimethamine partner within the artemisinin-based combination therapy

Given that the evolution and spread of resistance to sulfadoxine-pyrimethamine (SP) have been documented at a quick pace worldwide, the present study investigated the mutant Plasmodium falciparum dihydrofolate reductase 108-asparagine (dhfr 108 N) as a key marker of resistance to the combination among parasite isolates from Hodeidah. The association of parasitologic indices with the dhfr 108 N mutant allele was also studied. Ninety patients with microscopically confirmed P. falciparum infection from Hodeidah were included in the present study. Polymerase chain reaction-restriction fragment length polymorphism approach was adopted for the molecular detection of this marker. The dhfr 108 N was detected among about 61% of P. falciparum isolates, in its pure and mixed-type forms, from Hodeidah. Age, gender and residence of patients were not significant predictors for the presence of the mutant allele among parasite isolates. In contrast, a history of malaria and antimalarial drug intake in the year preceding the study as well as frequent antimalarial drug intake were significantly associated with this mutant allele. The high frequency of dhfr 108 N among parasites isolates makes the role of SP questionable as a partner with outstanding effectiveness within the ACT, at least, in the near future. SP plus artesunate should be monitored for its antimalarial efficacy at regular intervals, preferably through the molecular detection of resistance-associated mutations.