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"Assefa, Gudissa"
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Therapeutic efficacy and safety of artemether-lumefantrine for uncomplicated Plasmodium falciparum malaria treatment in Metehara, Central-east Ethiopia
2024
Background
Malaria remains a major global health problem although there was a remarkable achievement between 2000 and 2015. Malaria drug resistance, along with several other factors, presents a significant challenge to malaria control and elimination efforts. Numerous countries in sub-Saharan Africa have documented the presence of confirmed or potential markers of partial resistance against artemisinin, the drug of choice for the treatment of uncomplicated
Plasmodium falciparum
malaria. The World Health Organization (WHO) recommends regular surveillance of artemisinin therapeutic efficacy to inform policy decisions.
Methods
This study aimed to evaluate the therapeutic efficacy of artemether-lumefantrine (AL), which is the first-line treatment for uncomplicated
P. falciparum
malaria in Ethiopia since 2004. Using a single-arm prospective evaluation design, the study assessed the clinical and parasitological responses of patients with uncomplicated
P. falciparum
malaria in Metehara Health Centre, central-east Ethiopia. Out of 2332 malaria suspects (1187 males, 1145 females) screened, 80 (50 males, 30 females) were enrolled, followed up for 28 days, and 73 (44 males, 29 females) completed the follow up. The study was conducted and data was analysed by employing the per-protocol and Kaplan–Meier analyses following the WHO Malaria Therapeutic Efficacy Evaluation Guidelines 2009.
Results
The results indicated rapid parasite clearance and resolution of clinical symptoms, with all patients achieving complete recovery from asexual parasitaemia and fever by day (D) 3. The prevalence of gametocytes decreased from 6.3% on D0 to 2.5% on D2, D3, D7, and ultimately achieving complete clearance afterward.
Conclusion
The overall cure rate for AL treatment was 100%, demonstrating its high efficacy in effectively eliminating malaria parasites in patients. No serious adverse events related to AL treatment were reported during the study, suggesting its safety and tolerability among the participants. These findings confirm that AL remains a highly efficacious treatment for uncomplicated
P. falciparum
malaria in the study site after 20 years of its introduction in Ethiopia.
Journal Article
Therapeutic efficacy of Chloroquine for the treatment of uncomplicated Plasmodium vivax infection in Shewa Robit, Northeast Ethiopia
by
Alebachew Reta, Mihreteab
,
Alemu, Megbaru
,
Assefa, Gudissa
in
Adolescent
,
Adult
,
Antimalarials
2023
The development of drug resistance to chloroquine is posing a challenge in the prevention and control efforts of malaria globally. Chloroquine is the first-line treatment for uncomplicated P.vivax in Ethiopia. Regular monitoring of anti-malarial drugs is recommended to help early detection of drug-resistant strains of malaria parasites before widely distributed. The emergence of P.vivax resistance to chloroquine in the country endangers the efficacy of P.vivax treatment. This study aimed to assess the therapeutic efficacy of chloroquine among uncomplicated P.vivax infections at Shewa Robit Health Center, northeast Ethiopia.
One-arm in vivo prospective chloroquine efficacy study was conducted from November 2020 to March 2021. Ninety participants aged between 16 months to 60 years confirmed with P.vivax mono-infection microscopically were selected and treated with a 25 mg/kg standard dose of chloroquine over three days. Thick and thin blood smears were prepared and examined. Clinical examination was performed over 28 follow-up days. Hemoglobin concentration level was measured on days 0, 14, and 28.
Of the 90 enrolled participants, 86 (96%) completed their 28 days follow-up period. The overall cure rate of the drug was 98.8% (95% CI: 95.3-100%). All asexual stages and gametocytes were cleared within 48 hours with rapid clearance of fever. Hemoglobin concentration had significantly recovered between days 0 and 14, 0 and 28, and 14 and 28 days (P = 0.032, P<0.001, and P = 0.005), respectively. Fast resolution of clinical signs and symptoms was also observed. Severe adverse events were not recorded.
The present study revealed that chloroquine remains an efficacious and safe drug in the study setting for treating uncomplicated P.vivax in the study area. Large-scale continuous surveillance is needed to monitor the development of resistance in due time.
Journal Article
Spatiotemporal distribution and bionomics of Anopheles stephensi in different eco-epidemiological settings in Ethiopia
2024
Background
Malaria is a major public health concern in Ethiopia, and its incidence could worsen with the spread of the invasive mosquito species
Anopheles stephensi
in the country. This study aimed to provide updates on the distribution of
An. stephensi
and likely household exposure in Ethiopia.
Methods
Entomological surveillance was performed in 26 urban settings in Ethiopia from 2021 to 2023. A kilometer-by-kilometer quadrant was established per town, and approximately 20 structures per quadrant were surveyed every 3 months. Additional extensive sampling was conducted in 50 randomly selected structures in four urban centers in 2022 and 2023 to assess households’ exposure to
An. stephensi
. Prokopack aspirators and CDC light traps were used to collect adult mosquitoes, and standard dippers were used to collect immature stages. The collected mosquitoes were identified to species level by morphological keys and molecular methods. PCR assays were used to assess
Plasmodium
infection and mosquito blood meal source.
Results
Catches of adult
An. stephensi
were generally low (mean: 0.15 per trap), with eight positive sites among the 26 surveyed. This mosquito species was reported for the first time in Assosa, western Ethiopia.
Anopheles stephensi
was the predominant species in four of the eight positive sites, accounting for 75–100% relative abundance of the adult
Anopheles
catches. Household-level exposure, defined as the percentage of households with a peridomestic presence of
An. stephensi
, ranged from 18% in Metehara to 30% in Danan.
Anopheles arabiensis
was the predominant species in 20 of the 26 sites, accounting for 42.9–100% of the
Anopheles
catches. Bovine blood index, ovine blood index and human blood index values were 69.2%, 32.3% and 24.6%, respectively, for
An. stephensi
, and 65.4%, 46.7% and 35.8%, respectively, for
An. arabiensis
. None of the 197
An. stephensi
mosquitoes assayed tested positive for
Plasmodium
sporozoite, while of the 1434
An. arabiensis
mosquitoes assayed, 62 were positive for
Plasmodium
(10 for
P. falciparum
and 52 for
P. vivax
).
Conclusions
This study shows that the geographical range of
An. stephensi
has expanded to western Ethiopia. Strongly zoophagic behavior coupled with low adult catches might explain the absence of
Plasmodium
infection. The level of household exposure to
An. stephensi
in this study varied across positive sites. Further research is needed to better understand the bionomics and contribution of
An. stephensi
to malaria transmission.
Graphical Abstract
Journal Article
Evaluation of the effectiveness of Aquatain, Bacillus thuringiensis var. israelensis, and Temephos on Anopheles arabiensis and Anopheles stephensi larvae in the laboratory and field settings
2025
Background
The main tools to control malaria vectors in sub-Saharan Africa are long-lasting insecticidal nets and indoor residual spraying. However, their sustainability is threatened by the emergence of insecticide resistances, behavioral avoidance and presence of outdoor biting mosquito populations. Thus, complementary interventions such as larval source management, which includes larviciding, are required to achieve better results in malaria vector control. This study aimed to evaluate the effectiveness of three larvicides (Aquatain AMF
®
, Temephos and
Bacillus thuringiensis var. israelensis
) against larvae of
Anopheles arabiensisi
and
Anopheles stephensi
.
Methods
The tests on insectary colony and field-collected immature stages of the mosquitoes were conducted in the laboratory. For this, the third and fourth larval instars of
An. arabiensis
and
An. stephensi
were placed in trays measuring 50 cm × 40 cm, and larvicides were applied to the treatments while the control trays were left untreated. In addition, the larvicides were applied to selected natural habitats, and their effects on the reduction of the immature stages’ density were estimated.
Results
In the laboratory, susceptible
An. arabiensis
showed mortality rates of 95% with Aquatain, 100% with
Bti
and 100% with Temephos, while
An. stephensi
showed 60% with Aquatain, 84% with
Bti
and 100% with Temephos. The percentage of larval mortalities among wild
An. arabiensis
collected from the field and exposed to Aquatain,
Bti
and Temephos were 97%, 100% and 100%, respectively, whereas those of
An. stephensi
were 74%, 99% and 100%, respectively. During the natural field study, the reductions in immature stages were as follows: 77%, 96% and 95% in Adama; 89%, 95% and 94% in Metahara; and 92%, 84% and 96% in Awash for Aquatain,
Bti
and Temephos, respectively.
Conclusions
The three larvicides, Aquatain, Temephos and
Bti
, provided high levels of larviciding efficacies in both laboratory and field evaluations. Despite its effectiveness, Temephos caused the water to turn whitish and emitted a strong odor that made the community wary regarding the treated habitats. Therefore, we recommend using Aquatain in mosquito control programs as a complementary malaria vector control tool.
Graphical Abstract
Journal Article
Safety and therapeutic efficacy of artemether-lumefantrine in the treatment of uncomplicated Plasmodium falciparum malaria at Shecha health centre, Arba Minch, Ethiopia
by
Sime, Heven
,
Assefa, Gudissa
,
Hailgiorgis, Henok
in
Antimalarials
,
Antimalarials - adverse effects
,
Artemether - therapeutic use
2023
Background
In 2004, Ethiopia adopted artemether-lumefantrine (AL, Coartem
®
) as first-line treatment for the management of uncomplicated
Plasmodium falciparum
malaria. Continuous monitoring of AL therapeutic efficacy is crucial in Ethiopia, as per the World Health Organization (WHO) recommendation. This study aimed to assess the therapeutic efficacy of AL in the treatment of uncomplicated
P. falciparum
infection.
Methods
A 28 day onearm, prospective evaluation of the clinical and parasitological response to AL was conducted at Shecha Health Centre, Arba Minch town, Southern Ethiopia. Patients were treated with six-dose regimen of AL over three days and monitored for 28 days with clinical and laboratory assessments. Participant recruitment and outcome classification was done in accordance with the 2009 WHO methods for surveillance of anti-malarial drug efficacy guidelines.
Results
A total of 88 study participants were enrolled and 69 of them completed the study with adequate clinical and parasitological response. Two late parasitological failures were observed, of which one was classified as a recrudescence by polymerase chain reaction (PCR). The PCRcorrected cure rate was 98.6% (95% CI 92.3–100). AL demonstrated a rapid parasite and fever clearance with no parasitaemia on day 2 and febrile cases on day 3. Gametocyte clearance was complete by day three. No serious adverse events were reported during the 28 days follow-up.
Conclusion
The study demonstrated high therapeutic efficacy and good safety profile of AL. This suggests the continuation of AL as the first-line drug for the treatment of uncomplicated
P. falciparum
malaria in Ethiopia. Periodic therapeutic efficacy studies and monitoring of markers of resistance are recommended for early detection of resistant parasites.
Journal Article
Chloroquine has shown high therapeutic efficacy against uncomplicated Plasmodium vivax malaria in southern Ethiopia: seven decades after its introduction
2024
Background
Plasmodium vivax
malaria is a leading cause of morbidity in Ethiopia. The first-line treatment for
P. vivax
is chloroquine (CQ) and primaquine (PQ), but there have been local reports of CQ resistance. A clinical study was conducted to determine the efficacy of CQ for the treatment of
P. vivax
malaria in southern Ethiopia.
Methods
In 2021, patients with
P. vivax
mono-infection and uncomplicated malaria were enrolled and treated with 25 mg/kg CQ for 3 consecutive days. Patients were followed for 28 days according to WHO guidelines. The data were analysed using per-protocol (PP) and Kaplan‒Meier (K‒M) analyses to estimate the risk of recurrent
P. vivax
parasitaemia on day 28.
Results
A total of 88 patients were enrolled, 78 (88.6%) of whom completed the 28 days of follow-up. Overall, 76 (97.4%) patients had adequate clinical and parasitological responses, and two patients had late parasitological failures. The initial therapeutic response was rapid, with 100% clearance of asexual parasitaemia within 48 h.
Conclusion
Despite previous reports of declining chloroquine efficacy against
P. vivax
, CQ retains high therapeutic efficacy in southern Ethiopia, supporting the current national treatment guidelines. Ongoing clinical monitoring of CQ efficacy supported by advanced molecular methods is warranted to inform national surveillance and ensure optimal treatment guidelines.
Journal Article
Efficacy and safety of pyronaridine-artesunate (Pyramax®) for the treatment of uncomplicated Plasmodium vivax malaria in Northwest Ethiopia
by
Solomon, Hiwot
,
Assefa, Gudissa
,
Commons, Robert J.
in
Adult
,
Antimalarials - adverse effects
,
Biomedical and Life Sciences
2022
Background
Declining efficacy of chloroquine for the treatment
Plasmodium vivax
malaria has been reported in different endemic settings in Ethiopia. This highlights the need to assess alternative options for
P. vivax
treatment with artemisinin-based combination therapy, such as pyronaridine-artesunate. This treatment regimen has shown high efficacy for uncomplicated malaria in both Africa and Asia. However, limited data are available from Ethiopia. This study was conducted to assess the efficacy and safety of pyronaridine-artesunate for the treatment of uncomplicated
P. vivax
malaria in Northwest Ethiopia.
Methods
A single arm prospective efficacy study was conducted in the Hamusite area, Northwest Ethiopia. Fifty-one febrile adult patients with uncomplicated
P. vivax
malaria were enrolled between March and July 2021. Patients were treated with pyronaridine-artesunate once daily for three days. Clinical and parasitological parameters were monitored over a 42-day follow-up period using the standard World Health Organization protocol for therapeutic efficacy studies.
Results
A total of 4372 febrile patients were screened with 51 patients enrolled and 49 completing the 42-day follow-up period. The PCR-uncorrected adequate clinical and parasitological response (ACPR) was 95.9% (47/49; 95% CI 84.9–99.0) on day 42. Two patients had recurrences [4.0% (2/49); 95% CI 0.7–12.1] on days 35 and 42. The parasite clearance rate was rapid with fast resolution of clinical symptoms; 100% of participants had cleared parasitaemia on day 1 and fever on day 2. All 16 (31.4%) patients with gametocyte carriage on day 0 had cleared by day 1. There were no serious adverse events.
Conclusion
In this small study
,
pyronaridine-artesunate was efficacious and well-tolerated for the treatment of uncomplicated
P. vivax
malaria. In adults in the study setting, it would be a suitable alternative option for case management.
Journal Article
Therapeutic efficacy of pyronaridine-artesunate (Pyramax®) against uncomplicated Plasmodium falciparum infection at Hamusit Health Centre, Northwest Ethiopia
by
Parr, Jonathan B.
,
Assefa, Gudissa
,
Assefa, Ashenafi
in
Adult
,
Adults
,
Alternative interventions to facilitate malaria elimination
2023
Background
Early case detection and prompt treatment are important malaria control and elimination strategies. However, the emergence and rapid spread of drug-resistant strains present a major challenge. This study reports the first therapeutic efficacy profile of pyronaridine-artesunate against uncomplicated
Plasmodium falciparum
in Northwest Ethiopia.
Methods
This single-arm prospective study with 42-day follow-up period was conducted from March to May 2021 at Hamusit Health Centre using the World Health Organization (WHO) therapeutic efficacy study protocol. A total of 90 adults ages 18 and older with uncomplicated falciparum malaria consented and were enrolled in the study. A standard single-dose regimen of pyronaridine-artesunate was administered daily for 3 days, and clinical and parasitological outcomes were assessed over 42 days of follow-up. Thick and thin blood films were prepared from capillary blood and examined using light microscopy. Haemoglobin was measured and dried blood spots were collected on day 0 and on the day of failure.
Results
Out of 90 patients, 86/90 (95.6%) completed the 42-day follow-up study period. The overall PCR-corrected cure rate (adequate clinical and parasitological response) was very high at 86/87 (98.9%) (95% CI: 92.2–99.8%) with no serious adverse events. The parasite clearance rate was high with fast resolution of clinical symptoms; 86/90 (95.6%) and 100% of the study participants cleared parasitaemia and fever on day 3, respectively.
Conclusion
Pyronaridine-artesunate was highly efficacious and safe against uncomplicated
P. falciparum
in this study population.
Journal Article
Investigating the association between household exposure to Anopheles stephensi and malaria in Sudan and Ethiopia: A case-control study protocol
by
Bashir, Abdelgadir
,
Solomon, Hiwot
,
Assefa, Gudissa
in
Analysis
,
Animals
,
Anopheles - parasitology
2024
Endemic African malaria vectors are poorly adapted to typical urban ecologies. However, Anopheles stephensi, an urban malaria vector formerly confined to South Asia and the Persian Gulf, was recently detected in Africa and may change the epidemiology of malaria across the continent. Little is known about the public health implications of An. stephensi in Africa. This study is designed to assess the relative importance of household exposure to An. stephensi and endemic malaria vectors for malaria risk in urban Sudan and Ethiopia.
Case-control studies will be conducted in 3 urban settings (2 in Sudan, 1 in Ethiopia) to assess the association between presence of An. stephensi in and around households and malaria. Cases, defined as individuals positive for Plasmodium falciparum and/or P. vivax by microscopy/rapid diagnostic test (RDT), and controls, defined as age-matched individuals negative for P. falciparum and/or P. vivax by microscopy/RDT, will be recruited from public health facilities. Both household surveys and entomological surveillance for adult and immature mosquitoes will be conducted at participant homes within 48 hours of enrolment. Adult and immature mosquitoes will be identified by polymerase chain reaction (PCR). Conditional logistic regression will be used to estimate the association between presence of An. stephensi and malaria status, adjusted for co-occurrence of other malaria vectors and participant gender.
Findings from this study will provide evidence of the relative importance of An. stephensi for malaria burden in urban African settings, shedding light on the need for future intervention planning and policy development.
Journal Article
Baseline malaria prevalence at the targeted pre-elimination districts in Ethiopia
2021
Background
Encouraged by the previous success in malaria control and prevention strategies, the Ethiopian ministry of health launched malaria elimination with a stepwise approach by primarily targeting the low-transmission Districts and their adjacent areas/zones in order to shrink the country’s malaria map progressively. Hence, this community survey was conducted to establish baseline malaria information at the preliminary phase of elimination at targeted settings.
Methods
A community-based cross-sectional survey was conducted at 20 malaria-elimination targeted Districts selected from five Regional states and one city administration in Ethiopia. The GPS-enabled smartphones programmed with Open Data Kit were used to enumerate 9326 study households and collect data from 29,993 residents. CareStart™ Malaria
PAN (pLDH)
Rapid Diagnostic Tests (RDTs) were used for blood testing at the field level. Armpit digital thermometers were used to measure axillary temperature.
Result
Overall malaria prevalence by RDTs was 1.17% (339/28973). The prevalence at District levels ranged from 0.0 to 4.7%. The proportion of symptomatic cases (axillary temperature > 37.5
o
c) in the survey was 9.2% (2760/29993). Among the 2510 symptomatic individuals tested with RDTs, only 3.35% (84/2510) were malaria positive. The 75.2% (255/339) of all malaria positives were asymptomatic. Of the total asymptomatic malaria cases, 10.2% (26/255) were under-five children and 89.8% (229/255) were above 5 years of age.
Conclusion
The study shows a decrease in malaria prevalence compared to the reports of previous malaria indicator surveys in the country. The finding can be used as a baseline for measuring the achievement of ongoing malaria elimination efforts. Particularly, the high prevalence of asymptomatic individuals (0.88%) in these transmission settings indicates there may be sustaining hidden transmission. Therefore, active case detection with more sensitive diagnostic techniques is suggested to know more real magnitude of residual malaria in the elimination-targeted areas.
Journal Article