Examining community perceptions of malaria to inform elimination efforts in Southern Mozambique: a qualitative study.

BACKGROUND: In a background of renewed calls for malaria eradication, several endemic countries in sub-Saharan Africa are contemplating malaria elimination nationally or sub-nationally. In Mozambique, a strategy to eliminate malaria in the south is underway in the context of low endemicity levels and cross-border initiatives to eliminate malaria in South Africa and Eswatini. In this context, a demonstration project aiming to interrupt malaria transmission through mass antimalarial drug administrations and intensified vector control programmes accompanied by community engagement and standard case management was implemented in the Magude District. To ensure the necessary uptake of these interventions, formative qualitative research explored the perceptions, beliefs, attitudes, and practices related to malaria, its prevention and control. The current article describes the results of this study. METHODS: Seventeen focus group discussions were conducted between September and October of 2015 with the community leaders (6), adult men (5), women of reproductive age (5), and traditional healers (1) in Magude prior to the implementation of the project interventions. Respondents discussed perceptions around malaria symptoms, causes, preventions, and treatments. RESULTS: Knowledge of malaria was linked to awareness of its clinical presentation, and on-going vector control programmes. Perceptions of malaria aetiology were fragmented but related mainly to mosquito-mediated transmission. Reported preventive measures mostly involved mosquito control although participants were aware of the protective limitations of vector control tools. Awareness of asymptomatic carriers and the risk of outdoor malaria transmission were varied. Fever and malaria-like symptoms triggered immediate care-seeking community at health facilities. The identified barriers to malaria treatment included fear/mistrust in Western medicine, distance to health facilities, and lack of transportation. CONCLUSIONS: Several constraints and opportunities will potentially influence malaria elimination in Magude. Malaria awareness, trust in health institutions, and the demand for chemoprophylaxis could facilitate new interventions, such as mass drug administration. A lack of awareness of asymptomatic carriers, inadequate understanding of residual transmission, and barriers to care seeking could jeopardize uptake. Hence, elimination campaigns require strong community engagement and grassroots mobilization.

Seroprevalence of African swine fever in pigs for slaughter in Leyte, Philippines.

Objective: This study aims to determine the seroprevalence of African swine fever (ASF) in pigs for slaughter in Leyte, Philippines. It underpins the concept that recovered and infected pigs from ASF are likely sent for slaughter to avoid perceived economic losses. Materials and Methods: A cross-sectional study was conducted from March to June 2023 in eight abattoirs, each representing both a city and a municipality in Leyte province. A total of 218 blood samples from 78 farms were examined for ASF virus (ASFV) (VP72) antibodies using a blocking enzyme-linked immunosorbent assay (ELISA) method. Descriptive and seroprevalence analyses were performed. Results: ASF antibodies were detected in pigs for slaughter from abattoirs in Baybay and Ormoc cities, showing a seroprevalence of 3.57% (1/28 pigs) and 2.27% (1/44 pigs), respectively. An apparent absence of ASF antibodies was observed among pigs for slaughter in Isabel, Villaba, Abuyog, Kananga, Dulag, and Macarthur. The farm-level seroprevalence was 2.56% (95% CI: 0.71%-8.88%), while the pig-level seroprevalence was 0.91% (95% CI: 0.25%-3.27%). Conclusion: Detecting ASF antibodies among pigs for slaughter implies exposure to the virus from the farm of origin. This means that, on some farms, ASF remains unreported or undiagnosed. Active surveillance is needed for early case detection and rapid response to control the spread of ASF in the country.

Periodicity of Ascaridia galli egg excretion in experimentally infected chicken in the Philippines.

The periodicity of parasite egg excretion refers to variations in the number of eggs produced across time, with significant implications in optimizing diagnostic procedures and conducting the Fecal Egg Count Reduction Test (FECRT). Here, we explore whether Ascaridia galli egg excretion varies across time under Philippine conditions, thus informing the best time to collect fecal samples during flock health examination. A time-course analysis was performed in chickens (N = 12) experimentally infected with A. galli, isolated from a naturally infected Philippine native chicken. We examined the fecal egg per gram (EPG) count at 3-h intervals for 3 days, starting from 5:00-6:00 h AM to the following day at 1:00-2:00 h AM. Our results showed a consistent daily egg excretion pattern with a peak EPG count in the morning that abruptly declined in the afternoon and lowest in the evening. The EPG counts correlated with the amount of excreta produced, suggesting that A. galli fecundity corresponds to the timing of host defecation. Our results imply that the best time to collect fecal samples for A. galli diagnosis and FECRT in Philippine conditions should be from sunrise until late morning when parasite EPG count and host excreta production are at their highest.

Prevalence of Toxocara canis infection in dogs and Toxocara egg environmental contamination in Baybay City, Leyte, Philippines.

Toxocara canis is a parasitic gastrointestinal nematode of dogs causing toxocariasis in humans, a neglected tropical disease. This study examined the burden of T. canis infection in dogs and egg contamination in school playgrounds and public parks in Baybay City, Leyte, Philippines. Fecalysis and egg detection in soils were performed to determine the parasite prevalence in dogs and the environment. In addition, pet owner's survey and GIS mapping were employed to identify the risk factors of infection and map the parasite distribution. Fecalysis revealed a T. canis prevalence of 64.44% (95% CI: 48.78-78.13) at the barangay level and 17.96% (95% CI: 14.12-21.80) at the animal level. Rural areas showed a much higher T. canis prevalence than urban. Factors associated with high T. canis infection included dog's age, specifically puppy (2-8 mo) relative to young (> 8-24 mo) [Adjusted Odds Ratio (AOR): 2.282; 95% CI: 1.137-4.579; p = 0.020] and adult (> 24 mo) (AOR: 3.542; 95% CI: 1.714-7.319; p = 0.001), access to dirty water (AOR: 2.749; 95% CI: 1.575-4.798; p < 0.001), and non-deworming (AOR: 2.961; 95%: CI 1.009-8.684; p = 0.048). Furthermore, we observed high Toxocara egg contamination in school playgrounds and public parks, with a prevalence of 51.11% (95% CI: 35.77-66.3) at the barangay level and 15.45% (95% CI: 10.67-20.23) in soil samples. This epidemiological study is the first in the central Philippines to report a high burden of T. canis infection in dogs and the environment, thus providing crucial data that will help understand the epidemiology of toxocariasis. Supplementary Information: The online version contains supplementary material available at 10.1007/s12639-022-01525-y.

Plasmodium falciparum sexual conversion rates can be affected by artemisinin-based treatment in naturally infected malaria patients.

BACKGROUND: Artemisinins (ART) are the key component of the frontline antimalarial treatment, but their impact on Plasmodium falciparum sexual conversion rates in natural malaria infections remains unknown. This is an important knowledge gap because sexual conversion rates determine the relative parasite investment between maintaining infection in the same human host and transmission to mosquitoes. METHODS: The primary outcome of this study was to assess the impact of ART-based treatment on sexual conversion rates by comparing the relative transcript levels of pfap2-g and other sexual ring biomarkers (SRBs) before and after treatment. We analysed samples from previously existing cohorts in Vietnam, Burkina Faso and Mozambique (in total, n=109) collected before treatment and at 12 h intervals after treatment. As a secondary objective, we investigated factors that may influence the effect of treatment on sexual conversion rates. FINDINGS: In the majority of infections from the African cohorts, but not from Vietnam, we observed increased expression of pfap2-g and other SRBs after treatment. Estimated parasite age at the time of treatment was negatively correlated with the increase in pfap2-g transcript levels, suggesting that younger parasites are less susceptible to stimulation of sexual conversion. INTERPRETATION: We observed enhanced expression of SRBs after ART-based treatment in many patients, which suggests that in natural malaria infections sexual conversion rates can be altered by treatment. ART-based treatment reduces the potential of a treated individual to transmit the disease, but we hypothesise that under some circumstances this reduction may be attenuated by ART-enhanced sexual conversion. FUNDING: Spanish Agencia Estatal de Investigación (AEI), European Regional Development Fund (ERDF, European Union), Belgium Development Cooperation (DGD), Canadian University Health Network (UHN), TransGlobalHealth-Erasmus Mundus (European Union).

Transcriptional Analysis of Tightly Synchronized Plasmodium falciparum Intraerythrocytic Stages by RT-qPCR.

In Plasmodium falciparum, the parasite responsible for the most severe forms of human malaria, many fundamental processes are controlled at the transcriptional level. Studies on diverse aspects of basic parasite biology as well as molecular epidemiology studies often rely on the ability to accurately measure transcript levels, but this is complicated by the cyclic expression patterns of the majority of malaria parasite genes. Here, we provide a complete workflow to measure transcript levels in P. falciparum intraerythrocytic blood stages, overcoming the confounding factors that are commonly encountered. The method described covers all the steps from synchronization of parasite cultures to reverse transcriptase quantitative PCR (RT-qPCR) analysis.

Artemisinin exposure at the ring or trophozoite stage impacts Plasmodium falciparum sexual conversion differently.

Malaria transmission is dependent on the formation of gametocytes in the human blood. The sexual conversion rate, the proportion of asexual parasites that convert into gametocytes at each multiplication cycle, is variable and reflects the relative parasite investment between transmission and maintaining the infection. The impact of environmental factors such as drugs on sexual conversion rates is not well understood. We developed a robust assay using gametocyte-reporter parasite lines to accurately measure the impact of drugs on sexual conversion rates, independently from their gametocytocidal activity. We found that exposure to subcurative doses of the frontline antimalarial drug dihydroartemisinin (DHA) at the trophozoite stage resulted in a ~ fourfold increase in sexual conversion. In contrast, no increase was observed when ring stages were exposed or in cultures in which sexual conversion was stimulated by choline depletion. Our results reveal a complex relationship between antimalarial drugs and sexual conversion, with potential public health implications.

Reporter lines based on the gexp02 promoter enable early quantification of sexual conversion rates in the malaria parasite Plasmodium falciparum.

Transmission of malaria parasites from humans to mosquito vectors requires that some asexual parasites differentiate into sexual forms termed gametocytes. The balance between proliferation in the same host and conversion into transmission forms can be altered by the conditions of the environment. The ability to accurately measure the rate of sexual conversion under different conditions is essential for research addressing the mechanisms underlying sexual conversion, and to assess the impact of environmental factors. Here we describe new Plasmodium falciparum transgenic lines with genome-integrated constructs in which a fluorescent reporter is expressed under the control of the promoter of the gexp02 gene. Using these parasite lines, we developed a sexual conversion assay that shortens considerably the time needed for an accurate determination of sexual conversion rates, and dispenses the need to add chemicals to inhibit parasite replication. Furthermore, we demonstrate that gexp02 is expressed specifically in sexual parasites, with expression starting as early as the sexual ring stage, which makes it a candidate marker for circulating sexual rings in epidemiological studies.

Prevalence, risk factors, and spatial distribution of Fasciola in carabao and intermediate host in Baybay, Leyte, Philippines.

Fasciolosis remains an important parasitic disease of ruminants in Southeast Asia. We investigated the prevalence and spatial distribution of Fasciola spp. in carabao (Bubalus bubalis) and snail intermediate hosts (IHs) in Baybay, Leyte, Philippines. Using one-stage cluster sampling, we examined 335 fecal samples of carabaos from 138 herds for Fasciola spp. eggs, and in parallel collected IH snail data in the area. Risk factor analyses were performed and GIS maps were created for Fasciola spp. prevalence and IH snail distribution. The prevalence of Fasciola spp. in animal and herd level was 63.58% and 86.96%, respectively. Risk factor analyses showed that increasing age and drinking from irrigation water were highly associated with Fasciola infection in carabaos. Inversely, access to wallowing ponds seemed to be a significant protective factor. Lymnaeid snail presence was higher in areas with intensive networks of irrigated water system and rivers, land elevation above sea level, and moderate vegetation. Our epidemiologic data suggest a high endemicity of Fasciola spp. in Baybay, Leyte and present essential factors to consider in implementing control measures.

Anthelmintic activity of Moringa oleifera seed aqueous and ethanolic extracts against Haemonchus contortus eggs and third stage larvae.

Haemonchus contortus is one of the prevalent and pathogenic ruminant parasites that has grown resistance to common anthelmintic treatment. This study evaluated the anthelmintic potential of Moringa oleifera seed ethanolic and aqueous extracts against H. contortus eggs and infective stage larvae (L3s). The efficacy of five extract concentrations (0.95, 1.95, 3.9, 7.8, and 15.6 mg/mL) were tested through egg hatch assay and larval motility test. Phytochemical tests were conducted to detect the different plant secondary metabolites in the extracts. In the ovicidal assay, the ethanolic and aqueous extracts showed 95.89% and 81.72% egg hatch inhibition at 15.6 mg/mL, respectively. The ovicidal activity of 15.6 mg/mL ethanolic extract was comparable with that of albendazole (p > 0.05). The LC50 against the eggs was recorded at 2.91 and 3.83 mg/mL for ethanolic and aqueous extracts, respectively. In the larvicidal assay, the ethanolic and aqueous extracts exhibited 56.94% and 92.50% efficacy at 7.8 mg/mL, respectively. The larvicidal activity of 7.8 mg/mL aqueous extract was similar statistically with that of ivermectin (p > 0.05). The LC50 against L3s was recorded at 6.96 and 4.12 mg/mL for ethanolic and aqueous extracts, respectively. The secondary metabolites detected were tannins in ethanolic extract and saponins in aqueous extract. Both extracts inhibited larvae formation inside the eggs and rendered the L3s immobile. Therefore, M. oleifera seed extracts contained plant bioactive compounds with anthelmintic property against the eggs and L3s of H. contortus.

Prevalence and risk factors associated with gastrointestinal nematode infection in goats raised in Baybay city, Leyte, Philippines.

AIM: Gastrointestinal parasitism is a serious constraint affecting goat production in the Philippines. This study aimed to determine the prevalence and associated risk factors of gastrointestinal nematode infection in goat-populated barangays of Baybay City, Leyte. MATERIALS AND METHODS: A total of 81 households or farms were interviewed, and 450 goats were sampled for fecalysis. Fecal egg count along with egg morphological identification and coproculture for third stage larvae identification were conducted. Descriptive statistics and logistic regression analyses were carried out to determine the farm- and animal-level prevalence and risk factors. RESULTS: Fecalysis revealed the presence of strongyle and Trichuris spp. with a farm-level prevalence of 100% and 4.94%, respectively; and animal-level prevalence of 96.22% and 4.44%, respectively. The identified strongyle genera per barangay were Haemonchus spp. (34.79%), Trichostrongylus spp. (33.29%), Oesophagostomum spp. (24.21%), Cooperia spp. (6.93%), and Chabertia spp. (0.79%). Goats older than 12 months were four times more likely to present high strongyle burden when compared to goats <6 months. With each month increase in goat's age, the odds of acquiring strongyle infection also increased by 1.07 times. Animals kept in goat house with cemented flooring have lower odds of acquiring strongyle (odds ratio=0.12). Goats raised for leisure purposes and fed with carabao grass (Paspalum conjugatum) were 8.12 and 5.52 times more likely to acquire Trichuris, respectively. CONCLUSION: Most of the backyard goat raisers in Baybay City, Leyte, do not practice sound helminth control measures as shown by the high prevalence of gastrointestinal nematodes. The most relevant risk factors for gastrointestinal nematode infection were the age of the goat, type of goat house's flooring, purpose of raising goats, and feeding practices.