Prevalence and risk factors associated with asymptomatic malaria among school children: repeated cross-sectional surveys of school children in two ecological zones in Ghana.

BACKGROUND: Asymptomatic Plasmodium infections significantly drive malaria transmission and impact control and elimination strategies, but are largely uncharacterized. We investigated the prevalence and risk factors of asymptomatic malaria infections to inform malaria control strategies in Ghana. METHOD: Five cross-sectional surveys were conducted at the end of the peak transmission season (August-September) on 4892 school children aged between 6 and 14 years in two distinct ecological settings in Ghana between 2013 and 2017. The study sites were Begoro (forest ecology) and Cape Coast (coastal ecology). The children were screened for malaria parasites by microscopic examination of Giemsa-stained thin and thick blood films. Hemoglobin levels were measured using the Hemocue HB analyzer. In addition, height was measured and the height-for-age z-scores estimated from the reference population defined by WHO to determine children who were stunted. Proportions of categorical and means of continuous variables were compared using Chi-square test and Student's t-test respectively, and multivariable logistic regression was done to assess risk factors associated with asymptomatic infections. RESULTS: The overall prevalence of asymptomatic malaria in the school children was higher in Begoro compared to Cape Coast (27% (95% CI: 17, 24%) vs. 24% (95% CI: 17, 24%), p value = 0.04). The study recorded three species of Plasmodium (Plasmodia falciparum, malariae, and ovale) in both sites. Plasmodium falciparum was the predominant species, accounting for about 85% of infections in both study sites. The asymptomatic school children were more likely to be anaemic (OR = 2.01, p value< 0.001) and stunted in growth (OR = 1.46, p value< 0.001). Males carried more asymptomatic infection than females (OR = 1.18, p value = 0.015). School children aged 12-14 years had more asymptomatic infections than those aged 6-8 years (OR = 1.28, p value = 0.005). CONCLUSION: There is a considerable burden of asymptomatic malaria in the two regions of Ghana, which is associated with males, older children, anaemia, and stunted growth in children, and may have implications for malaria control and elimination strategies in Ghana.

The relationship between chitotriosidase activity and tuberculosis.

Chitotriosidase, secreted by activated macrophages, is a biomarker of activated macrophages. In this study, we explored whether chitotriosidase could be adopted as a biomarker to evaluate the curative effect on tuberculosis (TB). Five counties were randomly selected out of 122 counties/cities/districts in Hunan Province, China. Our cases were all TB patients who were newly diagnosed or had been receiving treatment at the Centers for Disease Control (CDCs) of these five counties between April and August in 2009. Healthy controls were selected from a community health facility in the Kaifu district of Changsha City after frequency-matching of gender and age with the cases. Chitotriosidase activity was evaluated by a fluorometric assay. Categorical variables were analysed with the χ 2 test. Measurement data in multiple groups were tested with analysis of variance and least significant difference (LSD). Correlation between chitotriosidase activity and the degree of radiological extent (DRE) was examined by Spearman's rank correlation test. The average chitotriosidase activity levels of new TB cases, TB cases with different periods of treatment (6 months) and the control group were 54·47, 34·77, 21·54, 12·73 and 10·53 nmol/h.ml, respectively. Chitotriosidase activity in TB patients declined along with the continuity of treatment. The chitotriosidase activity of both smear-positive and the smear-negative pulmonary TB patients decreased after 6 months' treatment to normal levels (P < 0·05). Moreover, chitotriosidase activity was positively correlated with DRE (r = 0·607, P < 0·001). Our results indicate that chitotriosidase might be a marker of TB treatment effects. However, further follow-up study of TB patients is needed in the future.

Antimalarial prescribing practices: a challenge to malaria control in Ghana.

OBJECTIVE: The study was conducted to determine antimalarial prescribing practices among prescribers in 2 of the 6 sentinel sites established to document antimalarial drug efficacy in Ghana in order to provide some explanation underlying chloroquine treatment failures in the country. SUBJECTS AND METHODS: The study was descriptive combining both qualitative and quantitative designs. The qualitative design involved in-depth interviews of general prescribers in the Wassa West and Kassena Nankana districts using an interview guide. The quantitative design involved a review of Outpatient Department prescriptions of 100 patients clinically diagnosed as having malaria within the year 2000 in each of the 7 selected health care facilities. RESULTS: The overall number of drugs prescribed per patient encounter was 4.3 in the Wassa West district and 3.0 in the Kassena Nankana district. The number of drugs per patient encounter was 5.4 and 3.7 in private and government health care facilities, respectively. The commonly prescribed antimalarial drug in all the health care facilities visited was chloroquine. However, only 9.8% of prescriptions in private health care facilities contained correct doses of chloroquine compared to 54% in government health care facilities (p = 0.000). Prescriptions containing chloroquine injections were least likely to have correct doses of chloroquine. CONCLUSION: The findings indicate that although chloroquine remained the first-line drug in the treatment of uncomplicated malaria in the two districts, the level of appropriateness of doses prescribed was generally low. Inappropriate doses of chloroquine prescribed were more prevalent in private than government health care facilities, and among prescriptions containing injections.