Insecticide resistance in Anopheles arabiensis from Ethiopia (2012-2016): a nationwide study for insecticide resistance monitoring.

BACKGROUND: Indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) remain the cornerstones of malaria vector control. However, the development of insecticide resistance and its implications for operational failure of preventative strategies are of concern. The aim of this study was to characterize insecticide resistance among Anopheles arabiensis populations in Ethiopia and describe temporal and spatial patterns of resistance between 2012 and 2016. METHODS: Between 2012 and 2016, resistance status of An. arabiensis was assessed annually during the long rainy seasons in study sites from seven of the nine regions in Ethiopia. Insecticide resistance levels were measured with WHO susceptibility tests and CDC bottle bioassays using insecticides from four chemical classes (organochlorines, pyrethroids, organophosphates and carbamates), with minor variations in insecticides tested and assays conducted between years. In selected sites, CDC synergist assays were performed by pre-exposing mosquitoes to piperonyl butoxide (PBO). In 2015 and 2016, mosquitoes from DDT and deltamethrin bioassays were randomly selected, identified to species-level and screened for knockdown resistance (kdr) by PCR. RESULTS: Intense resistance to DDT and pyrethroids was pervasive across Ethiopia, consistent with historic use of DDT for IRS and concomitant increases in insecticide-treated net coverage over the last 15 years. Longitudinal resistance trends to malathion, bendiocarb, propoxur and pirimiphos-methyl corresponded to shifts in the national insecticide policy. By 2016, resistance to the latter two insecticides had emerged, with the potential to jeopardize future long-term effectiveness of vector control activities in these areas. Between 2015 and 2016, the West African (L1014F) kdr allele was detected in 74.1% (n = 686/926) of specimens, with frequencies ranging from 31 to 100% and 33 to 100% in survivors from DDT and deltamethrin bioassays, respectively. Restoration of mosquito susceptibility, following pre-exposure to PBO, along with a lack of association between kdr allele frequency and An. arabiensis mortality rate, both indicate metabolic and target-site mutation mechanisms are contributing to insecticide resistance. CONCLUSIONS: Data generated by this study will strengthen the National Malaria Control Programme's insecticide resistance management strategy to safeguard continued efficacy of IRS and other malaria control methods in Ethiopia

Quantifying malaria endemicity in Ethiopia through combined application of classical methods and enzyme-linked immunosorbent assay: an initial step for countries with low transmission initiating elimination programme

Abstract Background In the context of reduced transmission of malaria, it is essential to re-evaluate and determine the level of transmission as it guides re-orientation of control measures which is appropriate to local disease epidemiology. However, little is known about level of malaria transmission in Ethiopia. The present study aimed to investigate the level of malaria transmission through combined application of classical methods and enzyme-linked immunosorbent assay (EIA) in low transmission settings of Ethiopia. Methods This study was conducted in June 2016 on 763 apparently healthy children 2–9 years of age. Children were recruited from ten sites representing different malaria transmission settings in Ethiopia. Splenomegaly rate, infection rate and EIA antibody test were used to determine endemicity. The data were analysed using SPSS 21.0 and Stata 12.0. Results The overall prevalence of malaria parasitaemia was 2.49% (95% CI 1.38–3.59) and 2.36% (95% CI 1.28–3.44) as detected using rapid diagnostic test and microscopy, respectively. Plasmodium falciparum accounted for 62.63% of the infections. The prevalence of parasitaemia significantly varied by altitude and localities; the highest (5.8%) in areas below 1500 m above sea level. Overall, splenomegaly rate was 1.70% (95% CI 0.78–0.2.66%), making the overall malaria transmission hypoendemic. Infection rate was higher among males (2.7%), but rate of splenomegaly was higher in females. Incongruent with spleen rate and parasitaemia, EIA showed a higher level of cumulative exposure to malaria with spatially localized and highly heterogeneous transmission. Overall, 126 (18.75%, 95% CI 15.79–21.71) of the children were positive for total malaria antibodies with significant variations with altitude, age and sex; the higher in areas of < 1500 m asl (25.8%), children ≥ 5 years (22.1%) and among males (20.9%). Conclusions Splenomegaly and parasitaemia are not good measures to show variations in the levels of malaria transmission in reduced and/or low endemic settings. The malaria antibody (i.e. serological) test seems to be a good measure of malaria endemicity showing greater degree of heterogeneity and localized risk of transmission. Thus, malaria elimination efforts need to be supported with serological indicators to identify patterns of foci of transmission to set priorities for interventions

Malaria Related Perceptions, Care Seeking after Onset of Fever and Anti-Malarial Drug Use in Malaria Endemic Settings of Southwest Ethiopia

<div><p>Background</p><p>Prompt care seeking and appropriate use of anti-malarial drugs are critical components of malaria prevention and control. This study assessed malaria related perceptions, care seeking behavior and anti-malarial drug use in malaria endemic settings of Ethiopia.</p><p>Methods</p><p>Data were generated from a community based cross-sectional study conducted among 798 households during January 2014 as part of a larger household behavioral study in three malaria endemic districts of Jimma Zone, Southwest Ethiopia. Both quantitative and qualitative data were collected and analyzed using SPSS 17.0 and STATA 12.0.</p><p>Results</p><p>In this study, only 76.1% of the respondents associated malaria to mosquito bite, and incorrect beliefs and perceptions were noted. Despite moderate level of knowledge (estimated mean = 62.2, Std Err = 0.7, 95% CI: 60.6–63.8%), quite high favorable attitude (overall estimated mean = 91.5, Std Err = 0.6, 95% CI: 90.1–92.9%) were recorded towards malaria preventive measures. The mean attitude score for prompt care seeking, appropriate use of anti-malarial drugs, LLIN use and Indoor Residual Spray acceptance was 98.5 (Std Err = 0.4, 95% CI:97.5–99.4), 92.7 (Std Err = 0.6 95% CI:91.5–93.9), 88.8 (Std Err = 0.5, 95% CI:85.5–92.1) and 86.5 (Std Err = 1.2, 95% CI: 83.9–89.1), respectively. The prevalence of fever was 2.9% (116/4107) and of the study participants with fever, 71.9% (95% CI: 65.5–78.3%) sought care and all of them consulted formal health care system. However, only 17 (19.8%) sought care within 24 hours after onset of fever. The frequency of care seeking was higher (77.8%, n = 21/27) and more prompt (28.6%, 6/21) for children under five as compared to old age groups despite it was not statistically significant (p > 0.05). However, higher median time of seeking first care was observed among Muslims and people who did not attend school (p < 0.05). Of those who used anti-malarial drugs, 9.1% indicated that they used it inappropriately through saving and/or sharing. Irregular availability of anti-malarial drugs; irregular presence of frontline health workers and misconceptions were mentioned to contribute to delayed care seeking and irrational use of anti-malarial drugs.</p><p>Conclusions</p><p>Although care seeking behavior for febrile illness was quite high in this community, the habit of prompt care seeking was very limited. Thus, malaria prevention and control programs need to take into account local misconceptions and wrong perceptions, and health system factors to achieve optimal health seeking behavior in such malaria endemic settings.</p></div

Pattern of seeking care after onset of fever by age and sex category, Jimma, Jan 2014.

<p>The frequency of seeking any care for fever was almost similar across age groups even though slightly higher for children under five (77.8%) as compared to other age groups. However, there was a slight gender disparity (male 77.4% versus female 71.0%). On the other hand, the frequency of seeking prompt care was relatively higher for children below the age five (28.6%) and lower for older children (age 6–18 years old) (15.8%). Likewise, more males (24.4%) were promptly taken to health facilities than females (15.6%) within a day. The frequency of using public health facilities tended to decline with age while the tendency of using private clinics increased with age which means that respondents tended to visit public health facilities for childhood fever whereas private clinics were chosen for adulthood fever (private clinic: 23.8% for children versus 33.4% for adults).</p

Kernel density estimates for malaria related knowledge and attitude scores by district, Jimma, Jan 2014.

<p>Overall, the density of knowledge score was lower as compared to the attitude score and in each district similar pattern was observed. This means despite low level of knowledge, the majority of the respondents had quite high favorable attitude towards malaria preventive measures (overall estimated mean = 91.5, Std Err = 0.6, 95% CI: 90.1–92.9%) towards malaria preventive measures. Generally, no single respondent scored less than 60% on the attitude scale. In contrast, there were respondents who had low level of knowledge (estimated mean = 62.2, Std Err = 0.7, 95% CI: 60.6–63.8%) on malaria and its preventive measures.</p

Perceptions and knowledge of respondents related to malaria, Jimma, Ethiopia (Jan 2014).

<p>Perceptions and knowledge of respondents related to malaria, Jimma, Ethiopia (Jan 2014).</p

Treatment seeking behavior after onset of fever among respondents, Jimma, Ethiopia (Jan 2014).

<p>Treatment seeking behavior after onset of fever among respondents, Jimma, Ethiopia (Jan 2014).</p

Anti-malarial drug use amonspeople with fever, Jimma. Jan2014.

<p>Of the household members who reported having fever, 88 (75.9%) used certain type of drug. However, only 51 (58.0%) used anti-malaria drugs and the remaining used non-anti-malarial drugs such as antipyretics, antibiotic and others. Of those who received anti-malarial drugs, 28(54.9%) received Chloroquine followed by ACT which accounted for 20 (39.3%). The majority (94.1%) of those who used anti-malarial drugs reported that they paid for it. Private clinics (45.1%), pharmacies (23.5%) and health centers (21.6%) constituted the major source of anti-malarial drugs. Only (9.8%) of those who used anti-malarial drugs obtained it from community health posts.</p

Reported prevalence of fever two weeks prior to the survey, Jimma, Ethiopia (Jan 2014).

<p>Reported prevalence of fever two weeks prior to the survey, Jimma, Ethiopia (Jan 2014).</p