Gender difference in the modified Insall-Salvati ratio in a black Kenyan population

The patellar tendon (PT) is part of the extensor mechanism of the knee attaching to the apex of the patella and tibial tuberosity. Gender differences of the PT have been described in terms of response to tensile forces. This response may be influenced by the patella height. An index for assessment of patellar height is the modified Insall-Salvati ratio. This ratio is used to classify the patella as either high riding (alta) or low riding (baja). Patella alta has been correlated to chronic patellar tendinopathy. Patellar tendinopathy is more common in males (6:1). The hypothesis of the study was that males would have a higher ratio and there was an expectation of more cases of patella alta among males. One hundred and two pairs of patellar tendons (58 male, 44 female) were thus obtained by simple random sampling from postmortem specimens at the Kenyatta National Hospital and Nairobi City mortuary. All the patellar tendons and patella bones were used to study the modified Insall-Salvati ratio, using a digital vernier caliper. This ratio was determined by dividing the length of the posterior lamina of the patellar tendon with the maximum diagonal length of the patella. The mean of the modified Insall-Salvati ratio for the right was 1.201 +/- 0.0901 in females and 1.1275 +/- 0.133 in males, p=0.001. The mean of the modified Insall-Salvati ratio for the left was 1.206 +/- 0.085 in females and 1.132 +/- 0.123 in males, p=0.001. Therefore, using the cut off value of 2.0, no cases of patella alta were observed. The modified Insall- Salvati ratio was thus observed to be higher in females in the Kenyan population. This observation of disparity between the expected and the observed results is confounding yet similar and consistent with previous findings in other populations. Research on the prevalence of patellar tendinopathy in the Kenyan population and radiological determination of the modified Insall-Salvati ratio is recommended.Keywords: Modified Insall-Salvati ratio, black Kenyan population

Regional differences in the cellularity and vascularity of the patellar tendon

The patellar tendon (PT) attaches to the apex of the patella and  tibial tuberosity. Its response to tensile forces is influenced by the distribution of fibroblasts and its vascularity. The vascularity and distribution of fibroblasts influence the tendons ability to repair microtears. Microtears of the PT result in patellar tendinopathy. There is however, paucity of data on the regional distribution of vascular and cellular elements in the PT which might explain why microtears occur in the posterior-proximal third. One hundred and two pairs of patellar tendons were obtained from postmortem  specimens. Sections from the proximal, middle and distal third from the anterior and posterior lamina of 20 pairs of the patellar tendon (10 male, 10 female) were processed for microscopy to demonstrate the cellularity and vascularity of the tendon. The vascularity was highest in the middle third of the anterior lamina. The posterior lamina of the tendon was less vascular than the anterior lamina. The posterior lamina was more cellular than the anterior with the proximal third showing the highest number of nuclei. These findings indicate that the pre-patellar genicular anastomosis contributes significantly to the vascularity of the anterior lamina while the anastomosis located in Hoffa’s fat pad may be less rich and thus resulting in lower vascularity for the posterior lamina. Lower vascularity implies less healing ability after microtears. Therefore, orthopedic surgeons should be aware of this precarious pattern of vascularity to the posterior lamina. The posterior lamina’s high cellularity especially in the proximal third indicates that it may experience greater stress and via  durotaxis more fibroblasts migrate to that region to produce more collagen fibers for resilience. The greater tensile stress  experienced by the posterior-proximal third and its lower  vascularity may explain why it is most susceptible to microtears.Key words: Patella tendon, regional differences, cellularity, vascularity, patella tendinopath

Evidence of co-exposure with Brucella spp, Coxiella burnetii, and Rift Valley fever virus among various species of wildlife in Kenya

Background Co-infection, especially with pathogens of dissimilar genetic makeup, may result in a more devastating impact on the host. Investigations on co-infection with neglected zoonotic pathogens in wildlife are necessary to inform appropriate prevention and control strategies to reduce disease burden in wildlife and the potential transmission of these pathogens between wildlife, livestock and humans. This study assessed co-exposure of various Kenyan wildflife species with Brucella spp, Coxiella burnetii and Rift Valley fever virus (RVFV). Methodology A total of 363 sera from 16 different wildlife species, most of them (92.6%) herbivores, were analysed by Enzyme-linked immunosorbent assay (ELISA) for IgG antibodies against Brucella spp, C. burnetii and RVFV. Further, 280 of these were tested by PCR to identify Brucella species. Results Of the 16 wildlife species tested, 15 (93.8%) were seropositive for at least one of the pathogens. Mean seropositivities were 18.9% (95% CI: 15.0–23.3) for RVFV, 13.7% (95% CI: 10.3–17.7) for Brucella spp and 9.1% (95% CI: 6.3–12.5) for C. burnetii. Buffaloes (n = 269) had higher seropositivity for Brucella spp. (17.1%, 95% CI: 13.0–21.7%) and RVFV (23.4%, 95% CI: 18.6–28.6%), while giraffes (n = 36) had the highest seropositivity for C. burnetii (44.4%, 95% CI: 27.9–61.9%). Importantly, 23 of the 93 (24.7%) animals positive for at least one pathogen were co-exposed, with 25.4% (18/71) of the positive buffaloes positive for brucellosis and RVFV. On molecular analysis, Brucella DNA was detected in 46 (19.5%, CI: 14.9–24.7) samples, with 4 (8.6%, 95% CI: 2.2–15.8) being identified as B. melitensis. The Fisher’s Exact test indicated that seropositivity varied significantly within the different animal families, with Brucella (p = 0.013), C. burnetii (p = <0.001) and RVFV (p = 0.007). Location was also significantly associated (p = <0.001) with Brucella spp. and C. burnetii seropositivities. Conclusion Of ~20% of Kenyan wildlife that are seropositive for Brucella spp, C. burnetii and RVFV, almost 25% indicate co-infections with the three pathogens, particularly with Brucella spp and RVFV

Ecological and subject-level drivers of interepidemic Rift Valley fever virus exposure in humans and livestock in Northern Kenya

Nearly a century after the first reports of Rift Valley fever (RVF) were documented in Kenya, questions on the transmission dynamics of the disease remain. Specifically, data on viral maintenance in the quiescent years between epidemics is limited. We implemented a cross-sectional study in northern Kenya to determine the seroprevalence, risk factors, and ecological predictors of RVF in humans and livestock during an interepidemic period. Six hundred seventy-six human and 1,864 livestock samples were screened for anti-RVF Immunoglobulin G (IgG). Out of the 1,864 livestock samples tested for IgG, a subset of 1,103 samples was randomly selected for additional testing to detect the presence of anti-RVFV Immunoglobulin M (IgM). The anti-RVF virus (RVFV) IgG seropositivity in livestock and humans was 21.7% and 28.4%, respectively. RVFV IgM was detected in 0.4% of the livestock samples. Participation in the slaughter of livestock and age were positively associated with RVFV exposure in humans, while age was a significant factor in livestock. We detected significant interaction between rainfall and elevation's influence on livestock seropositivity, while in humans, elevation was negatively associated with RVF virus exposure. The linear increase of human and livestock exposure with age suggests an endemic transmission cycle, further corroborated by the detection of IgM antibodies in livestock

A Comparative Study of the Physiochemical and Bacteriological Parameters of Potable Water from Different Sources in Kitui County, Kenya

Developing nations are experiencing an ever-increasing demand for safe water due to climate change and the ever-increasing human population. Various strategies including construction of shallow wells, boreholes and sand dams along the river are done to make water available to various households. However, availability of water sources near are faced with challenges of pollution from a variety of sources. The aim of this study was to determine the levels of selected bacteriological and physico-chemical parameters in three potable water sources namely Kiembeni borehole, Mwitasyano River and Kalundu Dam in Kitui County.  The quality of this water was compared to the standards for potable water prescribed by Kenya Bureau of Standards (KEBS). Representative sampling was conducted during the wet season (October 2019) and the dry season (August 2020) in the three sampling sites. The samples were analyzed for physico-chemical parameters: pH, color, turbidity, alkalinity, conductivity, iron, calcium, magnesium, hardness, chloride, fluoride, sulphates, ammonia, total dissolved solids and bacteriological parameters: total and fecal coliform. The analysis was performed at the Kenya Water Institute (KEWI) laboratory using standard procedures. The values obtained for the different water sources in the wet season and dry season were pooled and mean values calculated to determine the overall quality of drinking water. The results indicated that all the water sources had fecal coliform levels unsuitable for drinking water. Most of the values obtained for pH, color, alkalinity, conductivity, calcium, fluoride and sulphates in all sources of water were within the recommended potable water standards by KEBS. However, turbidity, iron and total coliform obtained values for borehole water samples were not within the recommended KEBS standards. The river and dam water samples were within the recommended standards for magnesium, hardness, chloride, ammonia and total dissolved solids. Although results indicate that some of the physico-chemical parameters were in conformance with the recommended standards, the overall bacteriological parameters render the water unsuitable for drinking.  Thus, public health intervention programmes should be focused on addressing various sources of water pollution including regular disinfection of water. Keywords: Water quality, Physico-chemical, Kitui County, Assessment DOI: 10.7176/JEES/12-11-05 Publication date: November 30th 202

Seroprevalence of Brucella spp. and Rift Valley fever virus among slaughterhouse workers in Isiolo County, northern Kenya

Brucella spp. and Rift Valley fever virus (RVFV) are classified as priority zoonotic agents in Kenya, based on their public health and socioeconomic impact on the country. Data on the pathogen-specific and co-exposure levels is scarce due to limited active surveillance. This study investigated seroprevalence and co-exposure of Brucella spp. and RVFV and associated risk factors among slaughterhouse workers in Isiolo County, northern Kenya. A cross-sectional serosurvey was done in all 19 slaughterhouses in Isiolo County, enrolling 378 participants into the study. The overall seroprevalences for Brucella spp. and RVFV were 40.2% (95% CI: 35.2–45.4) and 18.3% (95% CI: 14.5–22.5), respectively while 10.3% (95% CI 7.4%-13.8%) of individuals were positive for antibodies against both Brucella spp. and RVFV. Virus neutralisation tests (VNT) confirmed anti-RVFV antibodies in 85% of ELISA-positive samples. Our seroprevalence results were comparable to community-level seroprevalences previously reported in the area. Since most of the study participants were not from livestock-keeping households, our findings attribute most of the detected infections to occupational exposure. The high exposure levels indicate slaughterhouse workers are the most at-risk population and there is need for infection, prevention, and control programs among this high-risk group. This is the first VNT confirmation of virus-neutralising antibodies among slaughterhouse workers in Isiolo County and corroborates reports of the area being a high-risk RVFV area as occasioned by previously reported outbreaks. This necessitates sensitization campaigns to enhance awareness of the risks involved and appropriate mitigation measures

Drivers of respiratory syncytial virus seasonal epidemics in children under 5 years in Kilifi, coastal Kenya

Respiratory syncytial virus (RSV) causes significant childhood morbidity and mortality in the developing world. The determinants of RSV seasonality are of importance in designing interventions. They are poorly understood in tropical and sub-tropical regions in low- and middle-income countries. Our study utilized long-term surveillance data on cases of RSV associated with severe or very severe pneumonia in children aged 1 day to 59 months admitted to the Kilifi County Hospital. A generalized additive model was used to investigate the association between RSV admissions and meteorological variables (maximum temperature, rainfall, absolute humidity); weekly number of births within the catchment population; and school term dates. Furthermore, a time-series-susceptible-infected-recovered (TSIR) model was used to reconstruct an empirical transmission rate which was used as a dependent variable in linear regression and generalized additive models with meteorological variables and school term dates. Maximum temperature, absolute humidity, and weekly number of births were significantly associated with RSV activity in the generalized additive model. Results from the TSIR model indicated that maximum temperature and absolute humidity were significant factors. Rainfall and school term did not yield significant relationships. Our study indicates that meteorological parameters and weekly number of births potentially play a role in the RSV seasonality in this region. More research is required to explore the underlying mechanisms underpinning the observed relationships

On the static and dynamic properties of flax and Cordenka epoxy composites

Fibre reinforced composites have excellent specific properties and are widely sought after by engineers seeking to reduce mass. However, end of life disposal is a significant problem and so research into more sustainable natural fibre composites is extremely topical. This paper examines the applicability of natural fibre composites for high performance structural applications. Woven flax and regenerated cellulose (Cordenka) textiles were pre-impregnated with commercially available epoxy resins and consolidated into test laminates in an autoclave to determine their static (compressive, tensile, flexural) and dynamic (energy absorption) properties. The range of compressive strengths was 77.5–299.6 MPa. Tensile strengths ranged from 63 to 92.6 MPa and interlaminar shear strength (ILSS) from 10.7 to 23.3 MPa. Specific energy absorption (SEA) varied between 21.2–34.2 kJ/kg. Biotex flax combined with MTM49 resin matched the SEA of T300 carbon fibre using the same resin system and layup. This work has demonstrated that natural fibre composites have significant scope for use in structural applications but additional work is required on fibre to matrix bonding in order to maximise their properties whilst remaining an environmentally credible option