James Jafali

Does socio-economic status explain the differentials in malaria parasite prevalence? Evidence from The Gambia

BackgroundMalaria is commonly associated with poverty. Macro-level estimates show strong links between malaria and poverty, and increasing evidence suggests that the causal link between malaria and poverty runs in both directions. However, micro-level (household and population) analyses on the linkages between malaria and poverty have often produced mixed results.MethodsThe Gambia Malaria Indicator Survey (MIS) 2010/11 was carried out between November 2010 and January 2011. Laboratory-confirmed malaria and wealth quintiles were used to assess the association of socio-economic status and malaria infection in children and the general population. Simple and multiple logistic regressions and survey data analysis procedures, including linearized standard errors to account for cluster sampling and unequal selection probabilities were applied.ResultsChildren (six to 59 months) from the second, third, fourth and richest quintiles were significantly less likely to have malaria compared to children from the poorest quintiles. Children (five to 14 years) from the fourth and richest quintiles were also significantly less likely to have malaria compared to those from the poorest quintiles. The malaria burden has shifted from the under-five children (six to 59 months) to children aged five to 14 years. Malaria prevalence was significantly higher in the Central River Region compared to the Upper River Region; and males bear the malaria brunt more than females. Children (six to 59 months) and children (five to 14 years) living in houses with poor walls, floors, roofs and windows were significant associated with higher prevalence of malaria. However, in the general population, only poor wall housing materials were associated with higher prevalence of malaria.ConclusionsInvestments in strategies that address socio-economic disparities and improvements in the quality of housing could, in the long term, significantly reduce the malaria burden in the poorest communities.

Differences in T-cell responses between Mycobacterium tuberculosis and Mycobacterium africanum-infected patients.

In The Gambia, Mycobacterium tuberculosis (Mtb) and Mycobacterium africanum (Maf) are major causes of tuberculosis (TB). Maf is more likely to cause TB in immune suppressed individuals, implying differences in virulence. Despite this, few studies have assessed the underlying immunity to the two pathogens in human. In this study, we analyzed T‐cell responses from 19 Maf‐ and 29 Mtb‐infected HIV‐negative patients before and after TB chemotherapy following overnight stimulation of whole blood with TB‐specific antigens. Before treatment, percentages of early secreted antigenic target‐6(ESAT‐6)/culture filtrate protein‐10(CFP‐10) and purified protein derivative‐specific single‐TNF‐α‐producing CD4+ and CD8+ T cells were significantly higher while single‐IL‐2‐producing T cells were significantly lower in Maf‐ compared with Mtb‐infected patients. Purified protein derivative‐specific polyfunctional CD4+ T cells frequencies were significantly higher before than after treatment, but there was no difference between the groups at both time points. Furthermore, the proportion of CD3+CD11b+ T cells was similar in both groups pretreatment, but was significantly lower with higher TNF‐α, IL‐2, and IFN‐γ production in Mtb‐ compared with that of Maf‐infected patients posttreatment. Our data provide evidence of differences in T‐cell responses to two mycobacterial strains with differing virulence, providing some insight into TB pathogenesis with different Mtb strains that could be prospectively explored as biomarkers for TB protection or susceptibility.

Contextualizing the Informed Consent Process in Vaccine Trials in Developing Countries

Introduction: Most sponsors of clinical trials in Africa propose the use of complicated informed consenting procedures as in developed countries, including the translation of informed consent forms into local languages. Although well intentioned, this practice may be irrelevant and of no added value in settings where local languages are only spoken but not written. Recognizing this challenge, the ethics committee in The Gambia recommend a consent procedure that takes into account these local realities. The objective of this paper was to assess the effectiveness of this new procedure in conveying key trial information among participants in a vaccine trial in The Gambia. Methods: Consent was obtained from 1200 parents using the new procedure. Comprehension was then assessed using a tool that contained questions on key aspects of the trial. Results: Although the majority of respondents had no formal education, almost all of them had a sound understanding of the trial. Variables such as age, gender, education, ethnicity and occupation had minimal effect on comprehension. Discussion and Conclusion: Our data suggest that the new consent procedure is effective in conveying key research information to research participants. The procedure is promising in that it has eliminated the need for repeatedly translating and back-translating informed consents. It also guarantees that the study team expresses research concepts in the same way.

Mass administration of azithromycin and Streptococcus pneumoniae carriage: cross-sectional surveys in the Gambia

OBJECTIVE To evaluate the effect of repeated mass drug administration (MDA) of azithromycin in the Gambia on the nasopharyngeal carriage of Streptococcus pneumoniae and on the emergence of antibiotic-resistant strains. METHODS This study involved villages that participated in a cluster randomized trial comparing the effect of one versus three azithromycin MDA rounds on the prevalence of trachoma. Only villages in which most children received 7-valent pneumococcal conjugate vaccine were included. Three cross-sectional surveys were performed in two villages that received three annual MDA rounds: the first immediately before the third MDA round and the second and third, 1 and 6 months, respectively, after the third MDA round. The third survey also covered six villages that had received one MDA round 30 months previously. Pneumococcal carriage was assessed using nasopharyngeal swabs and azithromycin resistance was detected using the Etest. FINDINGS The prevalence of pneumococcal carriage decreased from 43.4% to 19.2% between the first and second surveys (P < 0.001) but rebounded by the third survey (45.8%; P = 0.591). Being a carrier at the first survey was a risk factor for being a carrier at the second (odds ratio: 3.71; P <  0.001). At the third survey, the prevalence of carriage was similar after one and three MDA rounds (50.3% versus 45.8%, respectively; P = 0.170), as was the prevalence of azithromycin resistance (0.3% versus 0.9%, respectively; P = 0.340). CONCLUSION Three azithromycin MDA rounds did not increase the prevalence of nasopharyngeal carriage of azithromycin-resistant S. pneumoniae strains compared with one round.

Awareness of diabetes mellitus among diabetic patients in the Gambia: a strong case for health education and promotion

BackgroundAwareness of various aspects of Diabetes Mellitus (DM) is essential for the prevention, management and control of the disease. However, several studies have consistently shown that awareness of DM in the general population is low. None of these studies, however, was conducted in The Gambia, even though the condition constitutes a major public health problem in the country. In this paper, we assessed the awareness of DM among diabetic patients attending the Medical Out-Patient Department (MOPD) of Royal Victoria Teaching Hospital (RVTH), Banjul.MethodsWe interviewed 200 patients attending the MOPD of RVTH. We used a tool containing questions on patient’s demographic characteristics and awareness of various aspects of DM including general knowledge on DM, causes, complications, management and prevention.ResultsOf the 199 patients who were aware of their condition, only 47% said they knew what DM is. Similarly, 53% of the study participants had no knowledge of the causes of DM and about 50% were not aware of the methods of prevention. 67% knew that DM can result to loss of sight while 46.5% knew that DM can cause poor wound healing. Few respondents knew that DM can lead to kidney failure (13.5%), skin sepsis (12.0%), heart failure (5.5%) and stroke (4.5%). Close to 50% of the respondent did not know how DM can be prevented. Level of education, duration of illness and knowledge of a family member with diabetes were important predictors of knowledge in our study.ConclusionOur study shows that the majority of patients attending the MOPD have poor knowledge on several aspects of DM. Hence, there is need for conscious efforts towards improving the level of awareness through health education and promotion, not limited to the hospital but also within the general population, as part of strategies to prevent, manage and control DM.

Haematological and biochemical reference values of Gambian infants

To establish haematological and biological reference values for Gambian infants.

Child Mortality after Discharge from a Health Facility following Suspected Pneumonia, Meningitis or Septicaemia in Rural Gambia: A Cohort Study.

Objective To measure mortality and its risk factors among children discharged from a health centre in rural Gambia. Methods We conducted a cohort study between 12 May 2008 and 11 May 2012. Children aged 2–59 months, admitted with suspected pneumonia, sepsis, or meningitis after presenting to primary and secondary care facilities, were followed for 180 days after discharge. We developed models associating post-discharge mortality with clinical syndrome on admission and clinical risk factors. Findings One hundred and five of 3755 (2.8%) children died, 80% within 3 months of discharge. Among children aged 2–11 and 12–59 months, there were 30 and 29 deaths per 1000 children per 180 days respectively, compared to 11 and 5 respectively in the resident population. Children with suspected pneumonia unaccompanied by clinically severe malnutrition (CSM) had the lowest risk of post-discharge mortality. Mortality increased in children with suspected meningitis or septicaemia without CSM (hazard ratio [HR] 2.6 and 2.2 respectively). The risk of mortality greatly increased with CSM on admission: CSM with suspected pneumonia (HR 8.1; 95% confidence interval (CI) 4.4 to 15), suspected sepsis (HR 18.4; 95% CI 11.3 to 30), or suspected meningitis (HR 13.7; 95% CI 4.2 to 45). Independent associations with mortality were: mid-upper arm circumference (MUAC) of 11.5–13.0 cm compared to >13.0 cm (HR 7.2; 95% CI 3.0 to 17.0), MUAC 10.5–11.4 cm (HR 24; 95% CI 9.4 to 62), and MUAC <10.5 cm (HR 44; 95% CI 18 to 108), neck stiffness (HR 10.4; 95% CI 3.1 to 34.8), non-medical discharge (HR 4.7; 95% CI 2.0 to 10.9), dry season discharge (HR 2.0; 95% CI 1.2 to 3.3), while greater haemoglobin (HR 0.82; 0.73 to 0.91), axillary temperature (HR 0.71; 95% CI 0.58 to 0.87), and oxygen saturation (HR 0.96; 95% CI 0.93 to 0.99) were associated with reduced mortality. Conclusion Gambian children experience increased mortality after discharge from primary and secondary care. Interventions should target both moderately and severely malnourished children.

Seasonality of Pneumococcal Nasopharyngeal Carriage in Rural Gambia Determined within the Context of a Cluster Randomized Pneumococcal Vaccine Trial

Background We conducted an ancillary study among individuals who had participated in a PCV-7 trial in rural Gambia, to determine the influence of season on the prevalence of pneumococcal carriage. Methods 636 individuals above 30 months of age were followed from 4 to 20 months after vaccination with PCV-7 or meningococcal-conjugate-vaccine. Nasopharyngeal swabs were collected periodically between November 2006 and June 2008. Overall, 4,495 NPS were collected. Results Prevalence of pneumococcal nasopharyngeal carriage in the study subjects (median age 11 years) was 55.0%; this prevalence decreased linearly with increasing age (p = 0.001). Prevalence of carriage was significantly higher during the dry than the rainy season for any pneumococcal carriage [57.6% versus 47.8% (p<0.001)], pneumococcal vaccine serotype carriage [10.3% versus 6.5% (p< 0.001)] and non-vaccine serotype carriage [49.7% versus 42.7% (p<0.001)]. Differences remained significant in the adjusted analysis. Conclusions In areas of Africa with marked variation in rainfall, seasonality of pneumococcal carriage needs to be considered when interpreting carriage data.

Antibodies against Haemophilus influenzae type b in The Gambia: Investigating the extent of protection across age groups

Following a landmark clinical trial, the vaccine against Haemophilus influenzae type b (Hib) was introduced in The Gambia in 1997. Whilst the immunogenicity of this vaccine is well established subsequent to the doses administered under the EPI schedule, little data exists assessing longevity of protection, using serology. Such data are needed however to predict the susceptibility to Hib at the population level. To determine antibody persistence in 5-6 year old fully vaccinated Gambian children compared with older children, adolescents and young adults, 427 serum samples from healthy 5-37 year old participants were tested for Hib antibodies using VaccZyme Human Anti-Hib ELISA kits. 86% of the children who had received 3 doses of Hib vaccine in infancy had Hib antibody concentrations ≥0.15 mg/l at the age of 5-6 years. This proportion was 76% for adolescents who had also largely been vaccinated and 90% for adults who had never received Hib vaccine. Although most participants had anti-Hib antibody above concentrations putatively defined as protective, significantly fewer had concentrations thought to confer long-term protection. This suggests a population with insufficient or waning antibody that may be susceptible to breakthrough disease and transmission.