The impact of targeted IRS, vector dynamics, and population movement on malaria in a high-transmission setting in northern Zambia

Background: The scale-up of malaria control efforts has led to a global decline in malaria burden, but progress has stalled or reversed in high-transmission regions. In Zambia, malaria cases increased annually since 2009 despite extensive malaria control activities, and malaria remains the most common cause of child mortality. To achieve the goal of malaria elimination in Zambia by 2021, drivers of transmission in high-burden areas must be identified and new intervention strategies must be developed and evaluated. Methods: The study was conducted in Nchelenge District, a high-transmission area in northern Zambia. The region has two main malaria vectors, Anopheles funestus s.s. and An. gambiae s.s., whose distribution varies spatially and temporally. Household surveys were conducted bimonthly from April 2012 to July 2017. Parasite prevalence was measured using rapid diagnostic tests (RDTs), and malaria vectors were collected with indoor light traps. Correlates of parasite prevalence and household vector abundance were identified, and the relationships between vector abundance and prevalence were defined. An evaluation was conducted to determine the impact of three years of targeted indoor residual spraying (IRS) with pirimiphos-methyl on vector abundance and parasite prevalence. Individual movement patterns were characterized using global positioning systems (GPS) data loggers and linked to malaria risk. Results: Parasite prevalence was approximately 50% across all participants, and an average of 7.0 An. funestus and 0.8 An. gambiae were collected per household. An. funestus counts were positively correlated with both rainy- and dry-season malaria transmission, and An. gambiae counts were positively associated with rainy-season transmission only. Within the area targeted for IRS, there was a 28% decline in parasite prevalence in the rainy season, and a 51% and 36% decline in An. funestus and An. gambiae counts. Three-quarters of participants spent time in both sprayed and unsprayed areas, and half spent at least an hour away from home per night during times of peak vector biting activity. Conclusions: Malaria transmission in Nchelenge District remains high with many barriers to control. Novel intervention strategies are needed to successfully reduce and interrupt transmission in high-burden areas, including year-round comprehensive vector control. Population movement patterns have the potential to increase malaria risk and must be considered in malaria control activities

Safety and efficacy of co-administered diethylcarbamazine, albendazole and ivermectin during mass drug administration for lymphatic filariasis in Haiti: Results from a two-armed, open-label, cluster-randomized, community study

In Haiti, 22 communes still require mass drug administration (MDA) to eliminate lymphatic filariasis (LF) as a public health problem. Several clinical trials have shown that a single oral dose of ivermectin (IVM), diethylcarbamazine (DEC) and albendazole (ALB) (IDA) is more effective than DEC plus ALB (DA) for clearing Wuchereria bancrofti microfilariae (Mf). We performed a cluster-randomized community study to compare the safety and efficacy of IDA and DA in an LF-endemic area in northern Haiti. Ten localities were randomized to receive either DA or IDA. Participants were monitored for adverse events (AE), parasite antigenemia, and microfilaremia. Antigen-positive participants were retested one year after MDA to assess treatment efficacy. Fewer participants (11.0%, 321/2917) experienced at least one AE after IDA compared to DA (17.3%, 491/2844, P<0.001). Most AEs were mild, and the three most common AEs reported were headaches, dizziness and abdominal pain. Serious AEs developed in three participants who received DA. Baseline prevalence for filarial antigenemia was 8.0% (239/3004) in IDA localities and 11.5% (344/2994) in DA localities (<0.001). Of those with positive antigenemia, 17.6% (42/239) in IDA localities and 20.9% (72/344, P = 0.25) in DA localities were microfilaremic. One year after treatment, 84% percent of persons with positive filarial antigen tests at baseline could be retested. Clearance rates for filarial antigenemia were 20.5% (41/200) after IDA versus 25.4% (74/289) after DA (P = 0.3). However, 94.4% (34/36) of IDA recipients and 75.9% (44/58) of DA recipients with baseline microfilaremia were Mf negative at the time of retest (P = 0.02). Thus, MDA with IDA was at least as well tolerated and significantly more effective for clearing Mf compared to the standard DA regimen in this study. Effective MDA coverage with IDA could accelerate the elimination of LF as a public health problem in the 22 communes that still require MDA in Haiti

Cholera prevention and control in refugee settings: Successes and continued challenges.

Cholera has long been viewed as a serious threat for refugee populations. In the 1980s and 90s, refugee camps proliferated in Africa and Asia as a result of large civil wars and environmental disasters. These camps experienced large-scale cholera outbreaks with regularity because of overcrowding, scarce clean water, and poor sanitation and hygiene practices. Death rates were often high because of preexisting malnutrition, comorbidities, and limited access to medical care. With appropriate clinical management, cholera mortality can be well below 1%, but it can be as high as 50%–60% without proper care. During this time, humanitarian organizations developed a variety of guidelines and standards to reduce morbidity and mortality during cholera outbreaks in these populations. Mobilization around these issues was greatly accelerated in 1994, when a particularly massive outbreak occurred among Rwandan refugees in the Lake Kivu region of Zaire (now the Democratic Republic of the Congo), and approximately 42,000 people died. In response to this unprecedented tragedy, the humanitarian community developed and adopted the Sphere standards for the minimumacceptable living conditions and availability of health services in refugee camps and other humanitarian responses

The experience of violence against children in domestic servitude in Haiti: Results from the Violence Against Children Survey, Haiti 2012

There have been estimates that over 150,000 Haitian children are living in servitude. Child domestic servants who perform unpaid labor are referred to as “restavèks.” Restavèks are often stigmatized, prohibited from attending school, and isolated from family placing them at higher risk for experiencing violence. In the absence of national data on the experiences of restavèks in Haiti, the study objective was to describe the sociodemographic characteristics of restavèks in Haiti and to assess their experiences of violence in childhood. The Violence Against Children Survey was a nationally representative, cross-sectional household survey of 13–24year olds (n=2916) conducted May–June 2012 in Haiti. A stratified three-stage cluster design was used to sample households and camps containing persons displaced by the 2010 earthquake. Respondents were interviewed to assess lifetime prevalence of physical, emotional, and sexual violence occurring before age 18. Chi-squared tests were used to assess the association between having been a restavèk and experiencing violence in childhood. In this study 17.4% of females and 12.2% of males reported having been restavèks before age 18. Restavèks were more likely to have worked in childhood, have never attended school, and to have come from a household that did not have enough money for food in childhood. Females who had been restavèks in childhood had higher odds of reporting childhood physical (OR 2.04 [1.40–2.97]); emotional (OR 2.41 [1.80–3.23]); and sexual violence (OR 1.86 [95% CI 1.34–2.58]) compared to females who had never been restavèks. Similarly, males who had ever been restavèks in childhood had significantly increased odds of emotional violence (OR 3.06 [1.99–4.70]) and sexual violence (OR 1.85 [1.12–3.07]) compared to males who had never been restavèks, but there was no difference in childhood physical violence. This study demonstrates that child domestic servants in Haiti experience higher rates of childhood violence and have less access to education and financial resources than other Haitian children. These findings highlight the importance of addressing both the lack of human rights law enforcement and the poor economic circumstances that allow the practice of restavèk to continue in Haiti