Genetic diversities of Mycobacterium tuberculosis complex species in Western Kenya.

Background: Tuberculosis (TB) remains a high-burden infectious disease worldwide. Mycobacterium tuberculosis complex (MTBC) is the aetiological agent of TB. Research Gap: The TB burden is significantly linked to the development of drug-resistant strains. Thus, there is an urgent need for close surveillance of MTBC circulating in a given region, such as Western Kenya, for treatment of TB. Aim: To determine the proportion of MTBC species, strains and genetic diversities in circulation in HIV/AIDS-prevalent regions, and Western Kenya in particular. The clinical MTBC isolates were collected from Moi Teaching and Referral Hospital (MTRH) at Eldoret-Kenya during 2013-14. All clinical MTBC isolates were confirmed by the gold standard method (Löwenstein-Jensen medium culture) before inclusion in the investigation. Methodology: Twelve-loci mycobacterium interspersed repetitive unit - variable-number tandem repeats (MIRU-VNTR) genotyping was performed to determine the circulating species/strains of MTBC using the www.miru-vntrplus.org web platform. Allelic diversity was calculated using the Hunter-Gaston diversity index (HGDI). Results: The species M. tuberculosis, Mycobacterium bovis, Mycobacterium africanum, Mycobacterium pinnipedii, Mycobacterium microti, Mycobacterium caprae and Mycobacterium canetti were identified in the MTBC population. These strains were found in the Beijing, Latin American Mediterranean, Uganda 1/2, East African Indian, Ilama, West African 1/2, Harlem, URAL, Ghana, Seal, Cameroon and Vole etc. regions of Western Kenya. Notably, some isolates had unknown (new/unassigned) species. The strains were grouped into nine clusters with a clustering rate of 31.18 % and a high allelic diversity index of 0.53 was observed. Conclusion: The present findings suggest that there is an urgent need for more awareness among healthcare professionals and stakeholders concerning the existence of foreign MTBC species/strains in Kenya. Furthermore, 12-loci MIRU-VNTR may not be suitable for the surveillance of MTBC strains in circulation in Kenya. Thus, high-resolution techniques such as whole-genome sequencing need to be adopted to resolve the genetic diversity and establish evolutionary trends for future and archived samples. This knowledge will be crucial in restraining TB, providing insights into new drug development, and developing prevention, control and treatment strategies for TB.

Burden of stigma among tuberculosis patients in a pastoralist community in Kenya: A mixed methods study.

BACKGROUND: Tuberculosis (TB) stigma remains a barrier to early diagnosis and treatment completion. Increased understanding of stigma is necessary for improved interventions to minimise TB stigma and its effects. The purpose of this study is to quantitatively measure TB stigma and to explore qualitatively its manifestation among TB patients in a rural Kenyan community. METHODS: This hospital based study using explanatory sequential mixed methods approach was conducted in 2016. In the quantitative part of the study, a questionnaire containing socio-demographic characteristics and scales measuring perceived TB stigma and experienced TB stigma, was administered to 208 adult pulmonary TB patients receiving treatment in West Pokot County. Respondents with high stigma were purposively selected to take part in in-depth interviews and focus group discussions. The qualitative data were collected through 15 in-depth interviews and 6 focus group discussions with TB patients. Descriptive and bivariate analysis was done for the quantitative data while the thematic analysis was done for qualitative data. RESULTS: The internal consistency reliability coefficients were satisfactory with Cronbach alphas of 0.87 and 0.86 for the 11-item and 12-item stigma measurement scale. The investigation revealed that TB stigma was high. The key drivers of TB stigma were the association of TB with HIV/AIDS and the fear of TB transmission. TB stigma was exemplified through patients being isolated by others, self-isolation, fear to disclose TB diagnosis, association of TB with human immunodeficiency virus (HIV) and lack of social support. Being a woman was significantly associated with high levels of both experienced stigma (p = 0.007) and perceived stigma (p = 0.005) while age, marital status, occupation and the patient's religion were not. CONCLUSION: There is a need to implement stigma reduction interventions in order to improve TB program outcomes.

Anopheles gambiae and Anopheles arabiensis population densities and infectivity in Kopere village, Western Kenya.

INTRODUCTION: This study was conducted in a sugar belt region of western Kenya interfacing epidemic and endemic malaria transmission. We investigated Anopheles gambiae sensu stricto (ss) and Anopheles arabiensis species compositions and densities, human host choice, and infectivity. METHODOLOGY: Mosquitoes were captured using pyrethrum spray catch technique and first identified based on morphology; species were confirmed by PCR. Blood meal preference and sporozoite rates were determined by ELISA. Parity rates and entomological inoculation rates (EIR) were determined. Seasonal densities were compared against environmental temperatures, relative humidity and rainfall. RESULTS: In total 2,426 An. gambiae were collected.  Out of 1,687 female blood-fed mosquitoes, 272 were randomly selected for entomological tests. An. gambiae ss and An. arabiensis comprised 75% (205/272) and 25% (68/272) of the selection, respectively. An. gambiae ss had higher preference for human blood (97%; n=263/272) compared with An. arabiensis, which mostly fed on bovines (88%; n=239/272).  The sporozoite and parity rates were 6% (16/272) and 66% (179/272) for An. gambiae ss and 2% (4/272) and 53% (144/272) for An. arabiensis respectively, while EIR was 0.78 infective bites/person/night.  Climate (ANOVA; F=14.2; DF=23) and temperature alone (r=0.626; t=3.75; p=0.001) were significantly correlated with vector densities. CONCLUSION: An. gambiae ss are the most efficient malaria vector mosquito species in Kopere village. Because An. gambiae ss largely rests and feeds indoors, use of indoor residual spray and insecticide-treated nets is likely the most suitable approach to malaria vector control in Kopere village and other parts of Kenya where this species is abundant.