A Rift Valley fever (RVF) outbreak occurred in at least five regions of Madagascar in 2021. The aim of this study was to provide an overview of the richness, abundance, ecology, and trophic preferences of mosquitoes in the Mananjary district and to investigate the distribution of mosquitoes that were RT-PCR-positive for RVFV. Three localities were prospected from 26 April to 4 May 2021, using light traps, BG-Sentinel traps baited with an artificial human odor, Muirhead-Thomson pit traps, and indoor pyrethroid spray catches. A total of 2806 mosquitoes belonging to at least 26 species were collected. Of 512 monospecific pools of mosquitoes tested with real-time RT-PCR, RVFV was detected in 37 pools representing 10 mosquito species. The RVFV-positive species were as follows: Aedes albopictus, Ae. argenteopunctatus, Anopheles coustani, An. gambiae s.l., An. mascarensis, An. squamosus/cydippis, Culex antennatus, Cx. decens, Cx. Tritaeniorhynchus, and Uranotaenia spp. Of the 450 tested engorged females, 78.7% had taken a blood meal on humans, 92.9% on cattle, and 71.6% had taken mixed (human–cattle) blood meals. This investigation suggests the potential role of mosquitoes in RVFV transmission within this epizootic/epidemic context and that the human populations at the three study sites were highly exposed to mosquitoes. Therefore, the use of impregnated mosquito nets as an appropriate prevention method is recommended.

An epizootic of rift valley fever (RVF) was suspected on 21 February 2021 in various districts of Madagascar, with a lab confirmation on 1 April 2021. A cross-sectional survey aiming to detect cases of RVF in humans and to study the circulation of rift valley fever virus (RVFV) in animals was conducted from 22 April to 4 May 2021 in the district of Mananjary. Blood samples from cattle and humans were tested using serological and molecular techniques. In cattle, the circulation of RVFV was confirmed between 5 February and 4 May 2021. The positivity rates of anti-RVFV IgG and IgM were 60% and 40%, respectively. In humans, the circulation of RVFV was observed from 1 April to 5 May 2021. The positivity rate of RVFV was estimated to be 11.7% by combining the results of the molecular and serological approaches. Of the 103 individuals who agreed to participate in the survey, 3 were determined to be positive by RT-PCR, and 10 had anti-RVFV IgM. Among them, one was positive for both. Given that previous studies have reported the circulation of RVFV during inter-epidemic periods and the occurrence of outbreaks due to imported RVFV in Madagascar, our findings suggest the importance of strengthening RVF surveillance from a “One Health” perspective by conducting syndromic and risk-based surveillance at the national and regional levels.

Malaria is a major public health problem in Madagascar, particularly in coastal areas. We conducted a randomized, controlled, parallel-group study of artemisinin-based combination therapy (ACT) in Mananjary and Farafangana, two localities on the rainy south-east coast of Madagascar, from March to September 2018. The efficacy and safety of artesunate + amodiaquine (ASAQ) and artemether + lumefantrine (AL) were assessed according to the WHO protocol with a 28-day follow-up. Children aged 6 months to 14 years with uncomplicated Plasmodium falciparum malaria were randomized to receive ASAQ or AL for three days (1:1). 347/352 (98.5%) randomized patients reached the study endpoint on day 28. Crude adequate clinical and parasitological response (ACPR) rates were 100% (95% CI: 98.8–100%) in the ASAQ group and 96% (95% CI: 93.1–98.9%) in the AL group (per protocol population). However, the PCR-corrected ACPR rate was 97.7% (95% CI: 95.4–100%) in the AL group. Two cases of recrudescence and three of re-infection were observed. Mild and moderate adverse events, including gastrointestinal and/or nervous disorders, were reported in 11.9% (42/352) of patients. We found that ASAQ and AL were safe and efficacious for treating uncomplicated P. falciparum malaria. They may be used for treatment at health facilities and at the community level, and for mass drug administration campaigns.

Background: The lack of rapid, sensitive, and affordable diagnostic tests that can distinguish a wide variety of respiratory pathogens at the point of care is an obstacle to the rapid implementation of control measures following events and epidemics. In addition, the absence of a standardized case definition to differentiate putative etiologies is a challenge to assessing disease burden. We aimed to identify the clinical spectrum of respiratory pathogens commonly associated with respiratory-tract infections in the context of disease surveillance. Methods: We used data obtained from prospective hospital-based severe acute respiratory infection (SARI) surveillance among children under five years of age from November 2010 to July 2013. Results: Intercostal recession and dyspnea could predict RSV infections, whereas headache and chills were more often observed during influenza A infection. Male patients were at a higher risk of developing RSV infection than female patients. Productive cough, chills, sweating, and weight loss were statistically associated with S. pneumonia infection. The presence of fever did not necessarily indicate an infection due to with RSV. Conclusions: Combined with other examinations, this study shows the interest of adding the syndromic approach in the panel of diagnostic criteria to rapidly identify infectious disease risk in areas where laboratory diagnostics are challenging. Given the current situation with COVID-19, this approach may help decision-makers to implement appropriate control measures.

: Despite significant progress in reducing malaria effects in recent decades, malaria remains a major challenge in Madagascar. Geographic and financial barriers often prevent individuals from seeking prompt care. Community health workers (CHWs) in many countries, including Madagascar, provide malaria case management services to children younger than 5 years old, although they typically do not treat older children and adults, leaving a gap for those living far from health facilities. To determine the efficacy of expanding malaria community case management (mCCM) to community members of all ages, a cluster randomized trial was conducted in one district of Madagascar from November 2020 to December 2021. Qualitative surveys were conducted to describe the acceptability and feasibility of this intervention among beneficiaries and CHWs. For this purpose, 87 semistructured interviews and 12 focus groups were conducted in intervention and control arms of the study to assess understanding of malaria, behaviors related to care seeking for fever, perceptions of CHW roles, and acceptability and feasibility of the age-expanded mCCM. Two major findings emerged. First, stakeholders found age-expanded mCCM to be consistent with existing CHW roles and practices. Age-expanded mCCM induced a recognition of adults’ susceptibility to malaria and led to a more accurate understanding of malaria. Second, structural and community-based challenges were not fully resolved by age-expanded mCCM, and some, such as the question of the cost of care, emerged after its implementation. Despite the fact that age-expanded mCCM was acceptable to beneficiaries and CHWs, successful scale-up will require addressing structural challenges and sociodemographic inequalities.

: The efficacy of artesunate + amodiaquine (ASAQ) and artemether + lumefantrine (AL) for treating malaria was investigated in Madagascar in 2020. A randomized parallel-group study was conducted at four health centers (Antsenavolo, Vohitromby, and Matanga in the southeastern region and Ankazomborona in the northwestern region). The therapeutic efficacy and safety of ASAQ and AL were assessed using the WHO protocol, with a 28-day follow-up period. Children aged 6 months to 14 years with uncomplicated Plasmodium falciparum ( P. falciparum ) malaria were randomly assigned to receive either ASAQ or AL. Genotyping assays for the pfK13 gene were conducted on P. falciparum isolates obtained from dry blood samples collected on Day 0. Of 765 enrolled patients, 709 (92.7%) reached the study endpoint. Among the per-protocol population, crude adequate clinical and parasitological response (ACPR) rates were 99%, 99%, 100%, and 100% for Antsenavolo, Vohitromby, Matanga, and Ankazomborona, respectively, in the ASAQ group and 98%, 91%, 90%, and 100% for the same locations, respectively, in the AL group. Polymerase chain reaction-corrected ACPR rates were 100% for the ASAQ group at all study sites, whereas for the AL group, they were 98.8% in Antsenavolo, 97.6% in Vohitromby, 100% in Matanga, and 100% in Ankazomborona. Day 3 slide positivity rates were 0%, 1%, 1%, and 0% for Antsenavolo, Vohitromby, Matanga, and Ankazomborona, respectively. During follow-up, mild and moderate adverse events, including gastrointestinal issues (abdominal pain and vomiting) and headache, were reported in 10.2% (72/709) of patients. Of 727 samples successfully analyzed for pfK13 , no mutation associated with artemisinin resistance was observed. The study results reveal that ASAQ and AL remain safe and efficacious for treating uncomplicated P. falciparum malaria in Madagascar.