Therapeutic efficacy of artemether-lumefantrine in the treatment of uncomplicated Plasmodium falciparum malaria in Arba Minch Zuria District, Gamo Zone, Southwest Ethiopia.

BACKGROUND: Artemether-lumefantrine (AL) has been the primary anti-malarial drug used to treat uncomplicated Plasmodium falciparum malaria in Ethiopia since 2004. However, there have been recent reports of AL resistance mutations in different African countries, including Ethiopia. This is concerning and requires periodic monitoring of anti-malarial drug resistance. Therefore, the current study aimed to evaluate the therapeutic efficacy of AL in treating uncomplicated P. falciparum malaria in the Arba Minch Zuria District, Gamo Zone, Southwest Ethiopia. METHODS: A single-arm prospective study with a 28-day follow-up period was conducted from July to October 2022. Capillary blood samples were collected for RDT and microscopic examination. The study enrolled monoinfected P. falciparum patients aged ≥ 18 years at Ganta Sira Health Post. Sociodemographic and clinical data were recorded, and a dried blood spot (DBS) was prepared for each participant. Nested polymerase chain reaction (nPCR) genotyping of the msp-1 and msp-2 genes was only performed for recurrent cases to distinguish between recurrence and reinfection. Data entry and analysis were performed using the WHO Excel spreadsheet and SPSS version 26. RESULTS: A total of 89 patients were enrolled, and 67 adequately completed the 28-day follow-up period. AL showed a 100% clearance rate for fever on day 2 and asexual parasites on day 3. Gametocytes were detected in 13.5% (12/89) of the participants. The gametocyte clearance rate was 58.3% (7/12) until day 7 and 100% (12/12) until day 14. Five participants developed recurrent malaria, three of whom experienced relapse and two of whom experienced reinfection. Based on the Kaplan-Meier survival analysis, the PCR-uncorrected and PCR-corrected cumulative incidence of success were 93.7% (95% CI 85.5-97.3) and 96.2% (95% CI 85.5-98.7), respectively. CONCLUSION: AL was efficacious in treating uncomplicated P. falciparum malaria in the study area. However, the detection of recurrent patients highlights the need for continuous efficacy studies in this area.

Exploring the impact of house screening intervention on entomological indices and incidence of malaria in Arba Minch town, southwest Ethiopia: A randomized control trial.

House is the major site for malaria infection where most human-vector contact takes place. Hence, improving housing might reduce the risk of malaria infection by limiting house entry of vectors. This study aimed to explore the impact of screening doors and windows with wire meshes on density and entomological inoculation rate (EIR) of malaria vector, and malaria incidence, and assess the acceptability, durability, and cost of the intervention. The susceptibility status of malaria vector was also assessed. A two-arm randomized trial was done in Arba Minch Town, southwest Ethiopia. 92 houses were randomly included in the trial. The baseline entomological and malaria prevalence data were collected. The mosquito sampling was done twice per household per month by Centers for Diseases Control and Prevention (CDC) light traps for six months. The baseline prevalence of malaria was assessed by testing 396 (83% of the 447 study participants) household members in all the eligible houses. The 92 houses were then randomized into control and intervention groups using mosquito and malaria prevalence baseline data to make the two groups comparable except the intervention. Then, we put wire-mesh on doors and windows of 46 houses. Post-screening mosquito collection was done in each household twice per month for three months. Each household member was visited twice per month for six months to assess malaria episodes. The frequency of damage to different structure of screening was measured twice. In-depth interview was conducted with 24 purposely selected household heads from intervention group. Speciation of Anopheles mosquito was done by morphological key, and the circum-sporozoite proteins (CSPs) analysis was done using enzyme-linked immunosorbent assay. A generalized estimating equation with a negative binomial distribution was used to assess the impact of the intervention on the indoor density of vectors. Clinical malaria case data were analyzed using Poisson regression with generalized linear model. Screening doors and windows reduced the indoor density of An. arabiensis by 48% (mean ratio of intervention to control = 0.85/1.65; 0.52) (P = .001). Plasmodium falciparum CSP rate was 1.6% (3/190) in the intervention houses, while it was 2.7% (10/372) in the control houses. The protective efficacy of screening intervention from CSP positive An. arabiensis was 41% (mean ratio of intervention to control = 1.6/2.7; 0.59), but was not statistically significant (P = .6). The EIR of An. arabiensis was 1.91 in the intervention group, whereas it was 6.45 in the control group. 477 participants were followed for clinical malaria (50.1% from intervention and 49.9% from the control group). Of 49 RDT positive cases, 45 were confirmed to be positive with microscopy. 80% (n = 36) cases were due to P. falciparum and the rest 20% (n = 9) were due to P. vivax. The incidence of P. falciparum in the intervention group was lower (IRR: 0.39, 95% CI: 0.2-0.80; P = .01) than in the control group. Using incidence of P. falciparum infection, the protective efficacy of intervention was 61% (95% CI: 18-83; P = .007). 97.9% of screened windows and 63.8% of screened doors were intact after eleven months of installation. Malaria mosquito was resistance (mortality rate of 75%) to the insecticide used for bed nets treatment. Almost all participants of intervention arm were willing to continue using screened doors and windows. Screening doors and windows reduced the indoor exposure to malaria vectors. The intervention is effective, durable and well-accepted. Hence, the existing interventions can be supplemented with house screening intervention for further reduction and ultimately elimination of malaria by reducing insecticide pressure on malaria vectors. However, further research could be considered in broad setting on different housing improvement and in the way how to scale-up for wider community.

A novel zoonotic genotype related to Echinococcus granulosus sensu stricto from southern Ethiopia.

Complete mitochondrial and two nuclear gene sequences of a novel genotype (GOmo) related to Echinococcus granulosus sensu stricto are described from a metacestode isolate retrieved from a human patient in southwestern Ethiopia. Phylogenetically, the genotype is positioned within the E. granulosus sensu stricto/Echinococcus felidis cluster, but cannot easily be allocated to either species. Based on different mitochondrial DNA markers, it is closest to the haplotype cluster that currently defines the species E. granulosus sensu stricto (which includes variants showing the widely cited G1, G2 and G3 sequences), but is clearly not part of this cluster. Pairwise distances between GOmo and E. granulosus sensu stricto are in the range of those between the most distant members of the Echinococcus canadensis complex (G6-10) that were recently proposed as separate species. At this stage, we prefer to list GOmo informally as a genotype rather than giving it any taxonomic rank because our knowledge rests on a single isolate from a dead-end host (human), and its lifecycle is unknown. According to data on molecularly characterised Echinococcus isolates from this region, GOmo has never been found in the usual livestock species that carry cystic echinococcosis and the possibility of a wildlife source of this newly recognised zoonotic agent cannot be excluded. The discovery of GOmo adds complexity to the already diverse array of cystic echinococcosis agents in sub-Saharan Africa and challenges hypotheses on the biogeographical origin of the E. granulosus sensu stricto clade.