Antimalarial resistance risk in Mozambique detected by a novel quadruplex droplet digital PCR assay.

While the Plasmodium falciparum malaria parasite continues to cause severe disease globally, Mozambique is disproportionally represented in malaria case totals. Acquisition of copy number variations (CNVs) in the parasite genome contributes to antimalarial drug resistance through overexpression of drug targets. Of interest, piperaquine resistance is associated with plasmepsin 2 and 3 CNVs (pfpmp2 and pfpmp3, respectively), while CNVs in the multidrug efflux pump, multidrug resistance-1 (pfmdr1), increase resistance to amodiaquine and lumefantrine. These antimalarials are partner drugs in artemisinin combination therapies (ACTs) and therefore, CNV detection with accurate and efficient tools is necessary to track ACT resistance risk. Here, we evaluated ~300 clinically derived samples collected from three sites in Mozambique for resistance-associated CNVs. We developed a novel, medium-throughput, quadruplex droplet digital PCR (ddPCR) assay to simultaneously quantify the copy number of pfpmp3, pfpmp2, and pfmdr1 loci in these clinical samples. By using DNA from laboratory parasite lines, we show that this nanodroplet-based method is capable of detecting picogram levels of parasite DNA, which facilitates its application for low yield and human host-contaminated clinical surveillance samples. Following ddPCR and the application of quality control standards, we detected CNVs in 13 of 229 high-quality samples (prevalence of 5.7%). Overall, our study revealed a low number of resistance CNVs present in the parasite population across all three collection sites, including various combinations of pfmdr1, pfpmp2, and pfpmp3 CNVs. The potential for future ACT resistance across Mozambique emphasizes the need for continued molecular surveillance across the region.

Preliminary Validation of the Pain Relief Motivation Scales.

OBJECTIVES: Pain typically prompts individuals to seek relief. This study aimed to develop and psychometrically validate the Pain Relief Motivation Scales, applying revised "reinforcement sensitivity theory" to measure the neuropsychological systems underlying motivation for pain relief. We hypothesized a 6-factor structure based on previous work, including one Behavioral Inhibition System (BIS) factor, one Fight-Flight-Freeze System factor, and 4 Behavioral Activation System (BAS) factors. METHODS: Items were generated by adapting the reinforcement sensitivity theory of personality questionnaire for relevance to pain relief. Adults with chronic pain were recruited internationally to participate in online survey batteries at baseline and 1 week later in 2021. We randomly split the sample to conduct exploratory factor analysis (n = 253) and confirmatory factor analysis (n = 253). Psychometric properties were estimated using the full sample (N = 506). RESULTS: Parallel analysis revealed that a 5-factor structure best fits the data (21 items): (1) hopelessness about pain relief (BIS), (2) hesitancy for engaging in pain treatments (BIS), (3) persistence in engaging in pain treatments (BAS), (4) relief reactivity (BAS), and (5) risky relief seeking (BAS). Acceptable internal consistency (Cronbach alpha = 0.68 to 0.80) and test-retest reliability (Intraclass correlation coefficients = 0.71 to 0.88) were observed. Construct validity varied from weak to moderate ( r = 0.02 to 0.45). CONCLUSION: As the first attempt to create an instrument measuring neuropsychological systems underlying motivation for pain relief, the findings show that additional work is needed to refine theory and psychometric rigor in this area. Cautiously, the results suggest that a BIS-BAS model, with minimal Fight-Flight-Freeze System contributions, might be useful for understanding the motivation for relief.

Severe snakebites in northern KwaZulu-Natal: treatment modalities and outcomes.

OBJECTIVE: We aimed to study the outcomes of severe snakebites in patients admitted to Ngwelezana Hospital in north-eastern KwaZulu-Natal, the seasonal variations, and the effectiveness and complications of antivenom. DESIGN: A prospective observational outcomes study was conducted over one year (1 June 2007 to 31 May 2008). The study group was from the north-eastern KwaZulu-Natal region of South Africa, with a population of approximately 3 million people, and included all patients bitten by snakes and admitted to the Ngwelezana Hospital Emergency Medicine Unit (EMU). Departmental practice guidelines were documented and followed. OUTCOME MEASURES: End-points for patient outcomes included transfer from the EMU to the ward, discharge home from the EMU, and follow-up of patients who required surgery or ICU care. RESULTS: A total of 243 snakebite patients were recorded. The highest incidence was in the summer months; 46 (18.93%) patients experienced one or more severe complications; 29 (11.93%) patients received some form of definitive management in hospital; and 22 (9.05%) of the latter patients received antivenom. Antivenom was administered to more children than adults. Adverse reactions to antivenom were common: an allergic response occurred in 4 (15.4%) patients, and anaphylaxis in 6 (23.1%); the highest incidence occurred in the <10-year-old age group. No deaths were recorded. CONCLUSIONS: Snakebites are common in the summer months in north eastern KwaZulu-Natal. Children are particularly vulnerable to snakebites and the effects of antivenom. Adverse reactions to antivenom are common. Severe snakebites that require antivenom should be managed in a hospital setting with advanced airway support. The syndromic approach to treatment is simple and effective.