Passive case detection of malaria in Ratanakiri Province (Cambodia) to detect villages at higher risk for malaria

Additional file 9. Spatial clusters of villages with significantly higher risk of falciparum malaria cases from 2010 to 2014 in Ratanakiri Province. Only significant clusters are showed. RR: Relative risk. LLR: Log likelihood ratio

Rodent abundance, stone bund density and its effects on crop damage in the Tigray highlands, Ethiopia

In areas of subsistence agriculture, a variety of soil conservation methods have been implemented in the last few decades to improve crop yields, however these can have unintended consequences such as providing habitat for rodent pests. We studied rodent population dynamics and estimated crop damage in high and low stone bund density fields for four cropping seasons in Tigray highlands, northern Ethiopia. Stone bunds are physical structures for soil and water conservation, and potentially habitat for rodents. We used a general model to relate the proportion of crop damage to rodent abundance, stone bund density and crop stages. Generally, rodent abundance remained relatively low during the study period, except during the fourth quarter of the 2010 cropping season. We found a positive correlation between rodent abundance and crop damage, and significant variation in rodent abundance and crop damage between high and low stone bund density fields. Furthermore, crop damage also varied significantly between crop stages. We concluded that Mastomys awashensis (Lavrenchenko, Likhnova and Baskevich 1998) and Arvicanthis dembeensis (Ruppel 1842) were the two most important crop pests in Tigray highlands causing significant damage. Fields with high stone bund density (~10m average distance apart) harbor more rodents and endure a significantly higher proportion of crop damage compared to fields with lower stone bund density (~15m average distance 4 apart). The fact that rodent abundances peaked during the reproductive stage of the crop and around harvest implies the need for management intervention before these crop stages are attained

Esperanza Window Traps for the collection of anthropophilic blackflies (Diptera: Simuliidae) in Uganda and Tanzania.

There is an increasing need to evaluate the impact of chemotherapeutic and vector-based interventions as onchocerciasis affected countries work towards eliminating the disease. The Esperanza Window Trap (EWT) provides a possible alternative to human landing collections (HLCs) for the collection of anthropophilic blackflies, yet it is not known whether current designs will prove effective for onchocerciasis vectors throughout sub-Saharan Africa. EWTs were deployed for 41 days in northern Uganda and south eastern Tanzania where different Simulium damnosum sibling species are responsible for disease transmission. The relative efficacy of EWTs and HLCs was compared, and responses of host-seeking blackflies to odour baits, colours, and yeast-produced CO2 were investigated. Blue EWTs baited with CO2 and worn socks collected 42.3% (2,393) of the total S. damnosum s.l. catch in northern Uganda. Numbers were comparable with those collected by HLCs (32.1%, 1,817), and higher than those collected on traps baited with CO2 and BG-Lure (25.6%, 1,446), a synthetic human attractant. Traps performed less well for the collection of S. damnosum s.l. in Tanzania where HLCs (72.5%, 2,432) consistently outperformed both blue (16.8%, 563) and black (10.7%, 360) traps baited with CO2 and worn socks. HLCs (72.3%, 361) also outperformed sock-baited (6.4%, 32) and BG-Lure-baited (21.2%, 106) traps for the collection of anthropophilic Simulium bovis in northern Uganda. Contrasting blackfly distributions were observed on traps in Uganda and Tanzania, indicating differences in behaviour in each area. The success of EWT collections of S. damnosum s.l. in northern Uganda was not replicated in Tanzania, or for the collection of anthropophilic S. bovis. Further research to improve the understanding of behavioural responses of vector sibling species to traps and their attractants should be encouraged

Serologic Surveillance for SARS-CoV-2 Infection among Wild Rodents, Europe

Publisher Copyright: © 2022 Centers for Disease Control and Prevention (CDC). All rights reserved.Peer reviewe

Injections, cocktails and diviners: therapeutic flexibility in the context of malaria elimination and drug resistance in Northeast Cambodia.

BACKGROUND: Adherence to effective malaria medication is extremely important in the context of Cambodia's elimination targets and drug resistance containment. Although the public sector health facilities are accessible to the local ethnic minorities of Ratanakiri province (Northeast Cambodia), their illness itineraries often lead them to private pharmacies selling "cocktails" and artemether injections, or to local diviners prescribing animal sacrifices to appease the spirits. METHODS: The research design consisted of a mixed methods study, combining qualitative (in-depth interviews and participant observation) and quantitative methods (household and cross-sectional survey). RESULTS: Three broad options for malaria treatment were identified: i) the public sector; ii) the private sector; iii) traditional treatment based on divination and ceremonial sacrifice. Treatment choice was influenced by the availability of treatment and provider, perceived side effects and efficacy of treatments, perceived etiology of symptoms, and patient-health provider encounters. Moreover, treatment paths proved to be highly flexible, changing mostly in relation to the perceived efficacy of a chosen treatment. CONCLUSIONS: Despite good availability of anti-malarial treatment in the public health sector, attendance remained low due to both structural and human behavioral factors. The common use and under-dosage of anti-malaria monotherapy in the private sector (single-dose injections, single-day drug cocktails) represents a threat not only for individual case management, but also for the regional plan of drug resistance containment and malaria elimination

Numbers, densities, and colocalization of AMPA- and NMDA-type glutamate receptors at individual synapses in the superficial spinal dorsal horn of rats

Additional file 1. Form for distribution of repellent bottles and recovery of empty bottles or household data sheet. This sheet was used to collect information from household representative during two-weekly bottle exchange. Each sheet is for each bottle exchange and for a household. Each household had a unique identification code (family code) which was used during the entire project

Households or hotspots? Defining intervention targets for malaria elimination in Ratanakiri Province, eastern Cambodia

Background. Malaria “hotspots” have been proposed as potential intervention units for targeted malaria elimination. Little is known about hotspot formation and stability in settings outside sub-Saharan Africa. Methods. Clustering of Plasmodium infections at the household and hotspot level was assessed over 2 years in 3 villages in eastern Cambodia. Social and spatial autocorrelation statistics were calculated to assess clustering of malaria risk, and logistic regression was used to assess the effect of living in a malaria hotspot compared to living in a malaria-positive household in the first year of the study on risk of malaria infection in the second year. Results. The crude prevalence of Plasmodium infection was 8.4% in 2016 and 3.6% in 2017. Living in a hotspot in 2016 did not predict Plasmodium risk at the individual or household level in 2017 overall, but living in a Plasmodium-positive household in 2016 strongly predicted living in a Plasmodium-positive household in 2017 (Risk Ratio, 5.00 [95% confidence interval, 2.09–11.96], P < .0001). There was no consistent evidence that malaria risk clustered in groups of socially connected individuals from different households. Conclusions. Malaria risk clustered more clearly in households than in hotspots over 2 years. Household-based strategies should be prioritized in malaria elimination programs in this region

Spatial clustering and risk factors of malaria infections in Ratanakiri Province, Cambodia

Background: Malaria incidence worldwide has steadily declined over the past decades. Consequently, increasingly more countries will proceed from control to elimination. The malaria distribution in low incidence settings appears patchy, and local transmission hotspots are a continuous source of infection. In this study, species-specific clusters and associated risk factors were identified based on malaria prevalence data collected in the north-east of Cambodia. In addition, Plasmodium falciparum genetic diversity, population structure and gene flows were studied.Method: In 2012, blood samples from 5793 randomly selected individuals living in 117 villages were collected from Ratanakiri province, Cambodia. Malariometric data of each participant were simultaneously accumulated using a standard questionnaire. A two-step PCR allowed for species-specific detection of malaria parasites, and SNPgenotyping of P. falciparum was performed. SaTScan was used to determine species-specific areas of elevated risk to infection, and univariate and multivariate risk analyses were carried out.Result: PCR diagnosis found 368 positive individuals (6.4%) for malaria parasites, of which 22% contained mixed species infections. The occurrence of these co-infections was more frequent than expected. Specific areas with elevated risk of infection were detected for all Plasmodium species. The clusters for Falciparum, Vivax and Ovale malaria appeared in the north of the province along the main river, while the cluster for Malariae malaria was situated elsewhere. The relative risk to be a malaria parasite carrier within clusters along the river was twice that outside the area. The main risk factor associated with three out of four malaria species was overnight stay in the plot hut, a human behaviour associated with indigenous farming. Haplotypes did not show clear geographical population structure, but pairwise Fst value comparison indicated higher parasite flow along the river.Discussion: Spatial aggregation of malaria parasite carriers, and the identification of malaria species-specific risk factors provide key insights in malaria epidemiology in low transmission settings, which can guide targeted supplementary interventions. Consequently, future malaria programmes in the province should implement additional specific policies targeting households staying overnight at their farms outside the village, in addition to migrants and forest workers

Rodent outbrakes in Sub-Saharan Africa

The impacts of rodents in both developing and developed countries are legendary. Myths and dogma about rodents and their outbreaks abound. They are imbedded in the culture and language of many societies. In many instances, it is the acceptance of these outbreaks by society that is our greatest challenge as crop protection special- ists or conservation biologists. The reason these episodic outbreaks become etched in the socio-cultural psyche from the sparsely populated uplands of Laos to the considerably more affl uent agricultural lands of Europe is that the impacts are often staggering—economically, socially, and even politically. There becomes a degree of acceptance of these impacts—rural people are born with rodents and will die with them. Their presence and impacts become a part of life; they become accepted and farmers become fatalistic about the losses they incur. Indeed, farmers in some areas of the Philippines say they “plant two rows of rice for rats, one for the birds, and seven for my family.” This need not be the case given the progress of our knowledge on the factors that cause population outbreaks of rodents. Indeed, it is our responsibility as scientists to document and make this knowledge widely available, particularly with more than 1 billion people suffering chronic hunger and rodent pests contributing signifi cantly to this burden (see Singleton 2003, Meerburg et al 2009). Moreover, in Asia, the 640 million people suffering from chronic hunger (FAO 2009) mainly rely on agriculture for their subsistence. The impetus for this collation of contributions from Asia, Africa, Oceania (Aus- tralia and New Zealand), Europe, and North America was an international conference on “Impacts of Rodent Outbreaks on Food Security in Asia” held following an increase in reports during 2007-09 of population outbreaks of rodents in the rice-cropping systems of Asia. In Asia and Africa, there are few widely accessible publications on these outbreaks. Most appear in the gray literature as brief reports in the annals of provincial or state departments of agriculture. They are doomed to gather dust and be lost to future generations. If this happens, then the lessons from previous outbreaks are not learned and therefore the infl uence of myth and dogma often outweighs evidence- based scientifi c knowledge developed from our successes and failures of management Rodent outbreaks: an age-old issue with a modern appraisal 1actions undertaken during previous outbreaks. One message, among many, that we hope to convey to readers is that we have made strong advances in our understand- ing of the factors that lead to rodent outbreaks (see also Singleton et al 2010). And, with such knowledge, local people and offi cials should be better placed to reduce the potentially devastating impacts associated with “fl oods” of rodents in the agricultural, periurban, and natural landscape