Widening geographic range of Rift Valley fever disease clusters associated with climate change in East Africa.

BACKGROUND: Recent epidemiology of Rift Valley fever (RVF) disease in Africa suggests growing frequency and expanding geographic range of small disease clusters in regions that previously had not reported the disease. We investigated factors associated with the phenomenon by characterising recent RVF disease events in East Africa. METHODS: Data on 100 disease events (2008-2022) from Kenya, Uganda and Tanzania were obtained from public databases and institutions, and modelled against possible geoecological risk factors of occurrence including altitude, soil type, rainfall/precipitation, temperature, normalised difference vegetation index (NDVI), livestock production system, land-use change and long-term climatic variations. Decadal climatic variations between 1980 and 2022 were evaluated for association with the changing disease pattern. RESULTS: Of 100 events, 91% were small RVF clusters with a median of one human (IQR, 1-3) and three livestock cases (IQR, 2-7). These clusters exhibited minimal human mortality (IQR, 0-1), and occurred primarily in highlands (67%), with 35% reported in areas that had never reported RVF disease. Multivariate regression analysis of geoecological variables showed a positive correlation between occurrence and increasing temperature and rainfall. A 1°C increase in temperature and a 1-unit increase in NDVI, one months prior were associated with increased RVF incidence rate ratios of 1.20 (95% CI 1.1, 1.2) and 1.93 (95% CI 1.01, 3.71), respectively. Long-term climatic trends showed a significant decadal increase in annual mean temperature (0.12-0.3°C/decade, p<0.05), associated with decreasing rainfall in arid and semi-arid lowlands but increasing rainfall trends in highlands (p<0.05). These hotter and wetter highlands showed increasing frequency of RVF clusters, accounting for 76% and 43% in Uganda and Kenya, respectively. CONCLUSION: These findings demonstrate the changing epidemiology of RVF disease. The widening geographic range of disease is associated with climatic variations, with the likely impact of wider dispersal of virus to new areas of endemicity and future epidemics.

Widening geographic range of Rift Valley fever disease clusters associated with climate change in East Africa.

Background: Recent epidemiology of Rift Valley fever (RVF) disease in Africa suggests growing frequency and expanding geographic range of small disease clusters in regions that previously had not reported the disease. We investigated factors associated with the phenomenon by characterizing recent RVF disease events in East Africa. Methods: Data on 100 disease events (2008 - 2022) from Kenya, Uganda, and Tanzania were obtained from public databases and institutions, and modeled against possible geo-ecological risk factors of occurrence including altitude, soil type, rainfall/precipitation, temperature, normalized difference vegetation index (NDVI), livestock production system, land-use change, and long-term climatic variations. Decadal climatic variations between 1980-2022 were evaluated for association with the changing disease pattern. Results: Of 100 events, 91% were small RVF clusters with a median of one human (IQR, 1-3) and 3 livestock cases (IQR, 2-7). These clusters exhibited minimal human mortality (IQR 0-1), and occurred primarily in highlands (67%), with 35% reported in areas that had never reported RVF disease. Multivariate regression analysis of geo-ecological variables showed a positive correlation between occurrence and increasing temperature and rainfall. A 1oC increase in temperature and 1-unit increase in NDVI, 1-3 months prior were associated with increased RVF incidence rate ratios (IRR) of 1.20 (95% CI 1.1,1.2) and 9.88 (95% CI 0.85, 119.52), respectively. Long-term climatic trends showed significant decadal increase in annual mean temperature (0.12 to 0.3oC/decade, P<0.05), associated with decreasing rainfall in arid and semi-arid lowlands but increasing rainfall trends in highlands (P<0.05). These hotter and wetter highlands showed increasing frequency of RVF clusters, accounting for 76% and 43% in Uganda and Kenya, respectively. Conclusion: These findings demonstrate the changing epidemiology of RVF disease. The widening geographic range of disease is associated with climatic variations, with the likely impact of wider dispersal of virus to new areas of endemicity and future epidemics. Key questions: What is already known on this topic?: Rift Valley fever is recognized for its association with heavy rainfall, flooding, and El Niño rains in the East African region. A growing body of recent studies has highlighted a shifting landscape of the disease, marked by an expanding geographic range and an increasing number of small RVF clusters.What this study adds: This study challenges previous beliefs about RVF, revealing that it predominantly occurs in small clusters rather than large outbreaks, and its association with El Niño is not as pronounced as previously thought. Over 65% of these clusters are concentrated in the highlands of Kenya and Uganda, with 35% occurring in previously unaffected regions, accompanied by an increase in temperature and total rainfall between 1980 and 2022, along with a rise in the annual number of rainy days. Notably, the observed rainfall increases are particularly significant during the short-rains season (October-December), aligning with a secondary peak in RVF incidence. In contrast, the lowlands of East Africa, where typical RVF epidemics occur, display smaller and more varied trends in annual rainfall.How this study might affect research, practice, or policy: The worldwide consequence of the expanding RVF cluster is the broader dispersion of the virus, leading to the establishment of new regions with virus endemicity. This escalation heightens the risk of more extensive extreme-weather-associated RVF epidemics in the future. Global public health institutions must persist in developing preparedness and response strategies for such scenarios. This involves the creation and approval of human RVF vaccines and therapeutics, coupled with a rapid distribution plan through regional banks.

BRCA1 and BRCA2 mutations and their clinical relevance in selected women diagnosed with triple-negative breast cancer in Kenya: a descriptive cross-sectional study.

Introduction: triple-negative breast cancer (TNBC) is a heterogeneous breast cancer type with a poor prognosis. About 25% of TNBC patients carry breast cancer susceptibility genes 1 and 2 (BRCA1 and BRCA2) mutations. Screening for BRCA mutations would facilitate early detection and initiation of personalized therapy, thus improving prognosis. However, this has not been explored in our population. We aimed at identifying BRCA1 and BRCA2 gene mutations and their clinical relevance among selected women with TNBC in Kenya. Methods: six participants enrolled in a larger descriptive cross-sectional study who met the inclusion criteria were selected. Structured questionnaires were used to obtain qualitative data. Deoxyribonucleic acid (DNA) was extracted from saliva. Whole exome sequencing of BRCA1 and BRCA2 genes using a next-generation sequencer was done. Results: overall, 83.3% of BRCA1 and BRCA2 gene mutations with clinical relevance were detected. Most of the variants (63%) were found in BRCA1 whereas 37% were found in BRCA2. Pathogenic mutations in BRCA1 gene included c.5513T>A, c.5291T>C, c.5297T>G, c.110C>A, c.5212G>C, c.122A>C, c.5117G>A, c.5095C>T, c.5054C>T, c.5053A>G, c.115T>A, c.5143A>G, and c.130T>G. Those in BRCA2 gene were c.7878G>A, c.9154C>T, c.8243G>A, c.7976G>A, c.8165C>G, c.8167G>C, and c.8168A>T. One variant (c.5352delG: p. Leu1785Terfs) not matching any in the BRCA Exchange and ClinVar databases was detected. Conclusion: our study revealed BRCA mutations that could be common among our population. Further, it has shown that BRCA1 and BRCA2 genetic mutations identified are of clinical relevance and there is a need to screen for these mutations in breast cancer patients to understand their implication in patient management outcomes.

Cytomorphological patterns of breast lesions among women with palpable breast lumps attending select teaching and referral hospitals in Kenya: a descriptive cross-sectional study.

Introduction: breast lumps account for a greater number of lesions in women attending surgical clinics in the developing world. Breast cancer which mostly presents as a breast lump is the leading cancer in Kenya, with an incidence of 12.5%. The study aims to describe the patterns of breast lesions in women presenting with palpable breast lumps in two major referral hospitals in Kenya. Methods: seven hundred and sixty-eight study participants with palpable lumps underwent fine needle aspiration cytology (FNAC). Sociodemographic data were captured using structured questionnaires. The FNAC materials were evaluated using the International Academy of Cytology Yokohama System (IACYS) and the lesions were classified into five-tier categories. Frequencies and percentages were used to summarize qualitative variables. Results: of 768 smears, 84.8% (n=651) were adequate for evaluation while 15.2% (n=117) were inadequate. Neoplastic lesions comprised 84.5% (n=550) and non-neoplastic 15.5% (n=101). Benign lesions accounted for 83.6% of the lesions followed by breast carcinoma (10.4%). Ductal carcinoma comprised 98.5% of cancerous lesions. The age group most affected with ductal carcinoma and suspicious lesions was 20-34 years (37.3% and 55.6% respectively). Fibroadenoma formed the bulk of the benign lesions identified (44.1%). Suspicious of malignancy was 4.1% (n=27). The age group with the most lesions (47.5%) was 20-34 years. Conclusion: a wide spectrum of breast lesions was established. Such include inflammatory, atypical, benign, suspicious of malignancy, and malignant lesions. Fibroadenoma was a common lesion diagnosed. The age group most affected by malignant lesions was 16-49 years, necessitating enhanced screening of women with breast lumps in our setups.

Bayesian Estimation of Diagnostic Accuracy of Three Diagnostic Tests for Bovine Tuberculosis in Egyptian Dairy Cattle Using Latent Class Models.

The aim of the present study was to calculate the sensitivity (Se) and specificity (Sp) of the single cervical tuberculin test (SCT), rapid lateral flow test (RLFT), and real-time polymerase chain reaction (RT-PCR) for the diagnosis of Mycobacterium bovis (M. bovis) infection in Egyptian dairy cattle herds within a Bayesian framework. The true M. bovis infection within-herd prevalence was assessed as a secondary objective. Data on the test results of SCT, RLFT, and RT-PCR for the detection of M. bovis were available from 245 cows in eleven herds in six major governorates in Egypt. A Bayesian latent class model was built for the estimation of the characteristics of the three tests. Our findings showed that Se of SCT (0.93 (95% Posterior credible interval (PCI): 0.89-0.93)) was higher than that of RT-PCR (0.83 (95% PCI: 0.28-0.93)) but was similar to the Se of RLFT (0.93 (95% PCI: 0.31-0.99)). On the contrary, SCT showed the lowest Sp estimate (0.60 (95% PCI: 0.59-0.65)), whereas Sp estimates of RT-PCR (0.99 (95% PCI: 0.95-1.00)) and RLFT (0.99 (95% PCI: 0.95-1.00)) were comparable. The true prevalence of M. bovis ranged between 0.07 and 0.71. In conclusion, overall, RT-PCR and RLFT registered superior performance to SCT, making them good candidates for routine use in the Egyptian bovine tuberculosis control program.

The detection dogs test is more sensitive than real-time PCR in screening for SARS-CoV-2.

In January 2020, the coronavirus disease was declared, by the World Health Organization as a global public health emergency. Recommendations from the WHO COVID Emergency Committee continue to support strengthening COVID surveillance systems, including timely access to effective diagnostics. Questions were raised about the validity of considering the RT-PCR as the gold standard in COVID-19 diagnosis. It has been suggested that a variety of methods should be used to evaluate advocated tests. Dogs had been successfully trained and employed to detect diseases in humans. Here we show that upon training explosives detection dogs on sniffing COVID-19 odor in patients' sweat, those dogs were able to successfully screen out 3249 individuals who tested negative for the SARS-CoV-2, from a cohort of 3290 individuals. Additionally, using Bayesian analysis, the sensitivity of the K9 test was found to be superior to the RT-PCR test performed on nasal swabs from a cohort of 3134 persons. Given its high sensitivity, short turn-around-time, low cost, less invasiveness, and ease of application, the detection dogs test lends itself as a better alternative to the RT-PCR in screening for SARS-CoV-2 in asymptomatic individuals.

Sensitivity and specificity of piroplasm indirect fluorescent antibody test and PCR for Theileria annulata infection in clinically asymptomatic large ruminants using Bayesian latent class analysis.

There is limited information about the accuracy of molecular and serological diagnostic assays for tropical theileriosis in asymptomatic carrier large ruminants. This study has estimated the sensitivity (Se) and specificity (Sp) of PCR and an indirect fluorescent antibody test (IFAT) in the diagnosis of tropical theileriosis in cattle and buffaloes via a Bayesian latent class analysis (BLCA) framework. Blood samples were collected from 70 cattle and water buffaloes (Bubalus bubalis) raised under a smallholder production system in different Egyptian localities. T. annulata infection status was detected by PCR, and IFAT and the test results were subjected to BLCA without assuming the existence of a reference test. Our findings showed that the performance of PCR was superior to that of IFAT. PCR showed a higher Se [0.83 (95% PCI: 0.63-0.98)] in comparison to IFAT [0.72 (95% PCI: 0.68-0.75)]. Similarly, PCR showed a higher Sp [0.95 (95% PCI: 0.77-1.00)] than IFAT [0.82 (95% PCI: 0.80-0.84)]. Se and Sp of the two tests did not differ by species implying that the diagnostics' performance for T. annulata infection in bovines is the same regardless of the species under consideration. In conclusion, PCR outperforms IFAT in the detection of T. annulata infection and can thus be applied to routine control of tropical theileriosis in endemic situations where cattle and buffaloes are kept under traditional smallholder production systems.

Risk factors for major external structural birth defects among children in Kiambu County, Kenya: a case-control study.

Background: Although major external structural birth defects continue to occur globally, the greatest burden is shouldered by resource-constrained countries with no surveillance systems. To our knowledge, many studies have been published on risk factors for major external structural birth defects, however, limited studies have been published in developing countries. The objective of this study was to identify risk factors for major external structural birth defects among children in Kiambu County, Kenya. Methods: A hospital-based case-control study was used to identify the risk factors for major external structural birth defects. A structured questionnaire was used to gather information retrospectively on maternal exposure to environmental teratogens, multifactorial inheritance, and sociodemographic-environmental factors during the study participants' last pregnancies.  Descriptive analyses (means, standard deviations, medians, and ranges) were used to summarize continuous variables, whereas categorical variables were summarized as proportions and percentages in frequency tables. Afterward, logistic regression analyses were conducted to estimate the effects of the predictors on the odds of major external structural birth defects in the country. Results: Women who conceived when residing in Ruiru sub-county (adjusted odds ratio [aOR]: 5.28; 95% CI: 1.68-16.58; P<0.01), and Thika sub-county (aOR: 0.27; 95% CI; 0.076-0.95; P =0.04); and preceding siblings with history of birth defects (aOR: 7.65; 95% CI; 1.46-40.01; P =0.02) were identified as the significant predictors of major external structural birth defects in the county. Conclusions: These findings pointed to MESBDs of genetic, multifactorial inheritance, and sociodemographic-environmental etiology. Thus, we recommend regional defect-specific surveillance programs, public health preventive measures, and treatment strategies to understand the epidemiology and economic burden of these defects in Kenya. We specifically recommend the integration of clinical genetic services with routine reproductive health services because of potential maternal genetic predisposition in the region.

Accuracy of diagnostic tests for respiratory syncytial virus infection within a paediatric hospital population in Kilifi County, Kenya.

Background: Respiratory syncytial virus (RSV)-induced lower respiratory tract disease is a prominent cause of hospitalisation among children aged <5 years in developing countries. Accurate and rapid diagnostic tests are central to informing effective patient management and surveillance efforts geared towards quantifying RSV disease burden. This study sought to estimate the sensitivity (Se), specificity (Sp) (along with the associated factors) and predictive values of a direct immunofluorescence test (IFAT), and two real-time reverse transcription polymerase chain reaction (rRT-PCR) assays for RSV infection within a paediatric hospital population: a multiplex rRT-PCR (MPX) and Fast-Track Diagnostics ® (FTD) Respiratory Pathogens 33 (Resp-33) rRT-PCR. Methods: The study enlisted 1458 paediatrics aged ≤59 months admitted with acute respiratory illness at the Kilifi County Hospital between August 2011 and December 2013. A Bayesian latent class modelling framework was employed to infer the tests' estimates based on the patients' diagnostic data from the three tests. Results: The tests posted statistically similar Se estimates: IFAT (93.7%, [90.7; 95.0]), FTD (97.8%, [94.6; 99.4]) and MPX (97.5%, [94.2; 99.3]). As for Sp, FTD registered a lower estimate (97.4%, [96.2; 98.2]) than MPX (99.7%, [99.0; 100.0]) but similar to IFAT (99.0%, [98.2; 99.6]). The negative and positive predictive values were strong (>91%) and closely mimicked the pattern given by the Se and Sp values respectively. None of the examined covariates (age, sex and pneumonia status) significantly influenced the accuracy of the tests. Conclusions: The evaluation found little to choose between the three diagnostic tests. Nonetheless, with its relative affordability, the conventional IFAT continues to hold promise for use in patient care and surveillance activities for RSV infection within settings where children are hospitalised with severe acute respiratory illness.

Accuracy of PCR, mycobacterial culture and interferon-γ assays for detection of Mycobacterium bovis in blood and milk samples from Egyptian dairy cows using Bayesian modelling.

The number of bovine tuberculosis (bTB) infected dairy herds in Egypt is growing and this calls for accurate and reliable diagnostic methods at cow level for cost-effective bTB eradication as culling of the whole herd is not economically sustainable. The present study aimed to estimate the sensitivity (Se) and specificity (Sp) of PCR, mycobacterial culture and interferon-γ (IFN-γ) assays for Mycobacterium bovis (M. bovis) detection in blood and milk samples from dairy cows in Egyptian dairy herds within a Bayesian framework. As a secondary objective, the distribution of true within-herd prevalence of M. bovis infection was estimated. Blood and milk samples were collected from 245 Holstein dairy cows in 11 Egyptian dairy herds and subjected to PCR, mycobacterial culture and IFN-γ testing. With respect to the detection of M. bovis in blood, IFN-γ recorded higher Se [0.97 (95% Posterior Credible Interval (PCI): 0.87-1.00)] than PCR [0.68 (95% PCI: 0.53-0.95)] and culture [0.22 (95% PCI: 0.13-0.37)]. However, Sp estimates of PCR [0.98 (95% PCI: 0.95-1.00)], culture [0.99 (95% PCI: 0.98-1.00)] and IFN-γ [0.97 (95% PCI: 0.88-1.00)] were comparable. As for milk samples, Se estimate of PCR [0.29 (95% PCI: 0.01-0.60)] was higher than that of culture [0.08 (95% PCI: 0.001-0.23)]. However, the Sp estimates of both tests were statistically similar. The estimated true within-herd prevalences of M. bovis varied across the tested bovine subpopulations and ranged between 0.06 and 0.66. In conclusion, IFN-γ registered a similar overall performance to PCR but was superior to mycobacterial culture. With its good accuracy and wide applicability, IFN-γ lends itself to use in the Egyptian bTB eradication program.

Prevalence of major external structural birth defects in Kiambu County, Kenya, 2014-2018.

INTRODUCTION: major external structural birth defects are typical and have been associated with childhood morbidity, mortality and lifelong resource-intensive disabilities. These defects continue to occur; however, they are yet to be recognized as public health problems in Kenya. The objective of this study was to estimate the prevalence of major external structural birth defects in Kiambu County in Kenya, 2014-2018. METHODS: a cross-sectional study design was adopted; a retrospective review of medical records was conducted between 2014 and 2018 abstracting 873 birth defects. Following a predetermined inclusion criterion, a five-year prevalence numerator of 362 cases was determined, whereas, a five-year prevalence denominator of 299,854 cases of registered live-births was obtained from the birth registrar. Annual prevalence estimates of 29 sub-groups and 6 groups of these defects were calculated as the number of cases (numerator) divided by the number of live-births (denominator). Associated 95% binomial exact confidence intervals were also computed and expressed per 100,000 live-births. RESULTS: defects of the musculoskeletal system, the central nervous system, orofacial, genital organs, eye and anus were observed. Defects of the musculoskeletal system were the most prevalent, ranging from 22.98 (95% CI: 11.87-40.13) to 116.9 (95% CI: 92.98-145.08) per 100,000 live-births. Defects of the central nervous system followed ranging between 13.40 (95% CI: 5.39-27.61) and 32.79 (95% CI: 20.79-49.19) per 100,000 live-births. CONCLUSION: despite musculoskeletal system defects being the most common group, hypospadias; a defect of the male genital organ was the most prevalent among the sub-group of these defects.

Bayesian evaluation of the performance of three diagnostic tests for Plasmodium falciparum infection in a low-transmission setting in Kilifi County, Kenya.

Background: Central to the successful elimination of Plasmodium falciparum malaria, are tests with superior capability of diagnosing low-density parasitaemias. Empirical evidence on the performance of the commonly available diagnostics (light microscopy (LM), rapid diagnostic tests (RDT) and polymerase chain reaction (PCR)) is needed to better inform case management and surveillance activities within primary health care settings where elimination of falciparum malaria is targeted. The objective of this study was to estimate the sensitivity (Se) and specificity (Sp) and predictive values of LM, RDT and PCR tests for P. falciparum infection, while evaluating the effect of specific covariates on the accuracy of the tests. Methods: The study enrolled 1,563 children via a cross-sectional survey for asymptomatic malaria and those presenting with symptomatic malaria to the Ngerenya dispensary, Kilifi County between March and December 2014. A Bayesian latent class model (BLCM) was fitted to the participants' diagnostic data obtained from blood samples that were screened for the presence of P. falciparum using the three tests. Results: The PCR assay registered a higher Se (97.6% [92.0; 99.7]) than LM (84.0% [74.8; 91.0]) but similar to RDT (92.2% [84.4; 97.0]). However, the assay showed a similar Sp (98.9% [98.2; 99.4]) to both RDT (99.4% [98.9; 99.7]) and LM (99.5% [99.0; 99.8]). Regarding predictive values, the tests yielded statistically similar estimates of Positive and negative predictive values (PPV and NPV). A serial interpretation of the results of RDT and LM raised the PPVs and NPVs to >98%. Conclusions: LM and RDT tests afford high Se and Sp in a low P. falciparum prevalence setting. A serial combination of the tests assures high PPV and NPV estimates. These elements, coupled with the wide deployment and affordability of the tests, lend the tests useful for guiding clinical care and surveillance activities for P. falciparum within elimination settings.

Association between umbilical cord hygiene and neonatal sepsis among neonates presenting to a primary care facility in Nairobi County, Kenya: a case-control study.

Background: Three-quarters of all annual neonatal deaths in developing countries are attributable to neonatal sepsis. In primary care settings, poor cord hygiene due to improper handling of the infant's cord is a major contributor to the occurrence of neonatal sepsis. The objective of this study was to describe the umbilical cord practices among mothers attending a primary care facility, assess the relationship between umbilical cord hygiene and neonatal sepsis, its impact on the population, as well as the influence of other neonatal and maternal factors on this relationship. Methods: A case-control study was conducted to assess the umbilical cord hygiene-neonatal sepsis relationship among neonates attending a primary care facility between August and October 2018. All cases were selected, while controls were systematically random sampled, as per study eligibility criteria. Exposure variables were summarized using descriptive statistics. A multivariable logistic regression model was fitted to evaluate the association between umbilical cord hygiene and neonatal sepsis adjusting for the effect of potential confounders. Subsequently, a population attributable fraction (PAF) was estimated. Results: The proportion of mothers with improper hygiene was 35.3%: 72.1% among the cases and 16.3% among the controls' caregivers. The odds of neonatal sepsis were 13 times higher (OR=13.24; 95% CI: [7.5; 23.4]) among infants whose caregivers had improper hygiene compared to those who had proper hygiene. None of the neonatal and maternal covariates confounded the umbilical cord hygiene-neonatal sepsis association. This odds ratio gave a PAF of 66.7% (95% CI: 62.5; 69.0). Conclusions: Improper cord hygiene is prevalent in this low resource setting. Improper cord hygiene has a strong positive association with neonatal sepsis. Observing good cord care practices could avert up to 67% of newborn infections. This calls for inclusion of comprehensive cord care practices in the antenatal care educational package.

Diagnostic performance of direct and indirect methods for assessing failure of transfer of passive immunity in dairy calves using latent class analysis.

Accurate diagnosis of failure of transfer of passive immunity (FTPI) in newborn calves is an essential component of dairy farm management plan. Several methods (direct and indirect) are available for diagnosis of FTPI in dairy calves. However, the indirect methods offer an advantage over the direct methods in not requiring an experienced veterinarian, rapid, cost efficient and can be performed under field-setting. The objective of this study was to estimate the diagnostic performance of radial immunodiffusion (RID) assay, transmission infrared (TIR) spectroscopy and digital Brix refractometer for diagnosis of FTPI in dairy calves using latent class models at four cut-off values of digital Brix refractometer. Holstein calves (n = 691) from 40 commercial dairy farms in the four Atlantic Canada provinces were blood-sampled and tested for detection of FTPI. Results showed that the number of calves with FTPI was 253 (36.6%) by RID, 194 (28.1%) by TIR and 204 (29.5%) by Brix refractometer at cut-off value of 8.2%. Estimates of SeRID was higher than SeTIR and SeBrix, at all Brix refractometer cut-offs, but with increase of Brix refractometer cut-off from 8.2 to 8.5%, SeRID and SeTIR were decreased from 96.0% (95% PCI: 88.0-99.0) and 79.0% (95% PCI: 70.0-85.0), to 92.0% (95% PCI: 77.0-99.0) and 74.0% (95% PCI: 61.0-82.0), respectively. SpRID and SpTIR were always higher than SpBrix at all tested cut-offs and were above 92.0%, and 96.0%, respectively. With increasing the cut-off of Brix refractometer from 8.2 to 8.5%, SeBrix estimate has remarkably increased from 79.0% (95% PCI: 70.0-96.0) to 95.0% (95% PCI: 87.0-100.0), respectively. Whilst, SpBrix was decreased from 95.0% (95% PCI: 91.0-98.0) at cut-off 8.2% to 84.0% (95% PCI: 78.0-94.0) at cut-off 8.5%. In conclusion, RID has a higher Se than TIR and Brix, if the latter is used with cut-offs of 8.2% or 8.3%. However, the higher the cut-off, the more comparable sensitivities of RID and digital Brix refractometer. The median estimate of SpTIR was always higher than SpRID and SpBrix at all tested cut-offs. However, the 95% confidence interval estimates of the three tests were overlapping across the tested cut-offs of digital Brix refractometer reflecting the inability to prefer a test over the other based on the Sp estimate.

Prevalence and risk factors for low back pain among university teaching staff in Nairobi, Kenya: a cross-sectional study.

Background: To date, there are few studies carried out on low back pain (LBP) among university teaching staff in developing countries despite academics being a high-risk group for LBP. In Kenya, to the best of our knowledge, there are no published studies that have investigated risk factors for LBP among teaching staff. The objectives of this study were to estimate the prevalence of LBP among teaching staff of the University of Nairobi (UoN), during the period June 2016 - May 2017, and to identify its socio-demographic and work-related risk factors. Methods: An analytical cross-sectional study design was used to estimate the prevalence and investigate the risk factors for LBP among 136 teaching staff of UoN. A semi-structured questionnaire was used to collect data on LBP history, work-related and socio-demographic characteristics of the study participants. The 12-month prevalence of LBP and its associated 95% exact binomial confidence interval were estimated. A mixed-effects logistic regression model was used to evaluate the relationship between the predictors and LBP. Results: The estimated 12-month prevalence of LBP was 64% (95% CI: 55.3%-72.0%). From the multivariable analysis, physical inactivity (aOR: 6.0; 95% CI: 1.2-29.6), office chairs without lumbar supports (aOR: 3.3; 95% CI: 0.1-0.9) and high workplace stress (aOR: 4.4; 95% CI: 1.1-17.5) were identified as significant risk factors for LBP among the respondents. Conclusions: This study has revealed a high burden of LBP among teaching staff of the UoN and undoubtedly mimics the situation in other higher learning institutions in Kenya. Physical inactivity, sitting on chairs without lumbar supports and workplace stress have been identified as modifiable risk factors for LBP among teaching staff. This suggests a need to strengthen advocacy for regular physical activity, team-building activities and investment in office infrastructure to mitigate the effects of LBP within learning institutions.

Effect of carryover and presampling procedures on the results of real-time PCR used for diagnosis of bovine intramammary infections with Streptococcus agalactiae at routine milk recordings.

The use of PCR tests as diagnostics for intramammary infections (IMI) based on composite milk samples collected in a non-sterile manner at milk recordings is increasing. Carryover of sample material between cows and non-aseptic PCR sampling may be incriminated for misclassification of IMI with Streptococcus agalactiae (S. agalactiae) in dairy herds with conventional milking parlours. Misclassification may result in unnecessary costs for treatment and culling. The objectives of this study were to (1) determine the effect of carryover on PCR-positivity for S. agalactiae at different PCR cycle threshold (Ct) cut-offs by estimating the between-cow correlation while accounting for the milking order, and (2) evaluate the effect of aseptic presampling procedures (PSP) on PCR-positivity at the different Ct-value cut-offs. The study was conducted in four herds with conventional milking parlours at routine milk recordings. Following the farmers' routine pre-milking preparation, 411 of 794 cows were randomly selected for the PSP treatment. These procedures included removing the first streams of milk and 70% alcohol teat disinfection. Composite milk samples were then collected from all cows and tested using PCR. Data on milking order were used to estimate the correlation between consecutively milked cows in each milking unit. Factors associated with the PCR-positivity for S. agalactiae were analyzed using generalized estimating equations assuming a binomially-distributed outcome with a logit link function. Presampling procedures were only significant using cut-off 37. A first-order autoregressive correlation structure provided the best correlation between consecutively milked cows. The correlation was 13%, 11%, 9% at cut-offs <40, 37, and 34, respectively. PSP did not reduce the odds of cows being PCR-positive for S. agalactiae. In conclusion, carryover and non-aseptic sampling affected the PCR results and should therefore be considered when samples from routine milk recordings are used. In relative terms, higher cut-offs resulted in higher between-cow correlation, but the absolute amount of carryover may not be affected although this was not tested.

Spatiotemporal patterns, annual baseline and movement-related incidence of Streptococcus agalactiae infection in Danish dairy herds: 2000-2009.

Several decades after the inception of the five-point plan for the control of contagious mastitis pathogens, Streptococcus agalactiae (S. agalactiae) persists as a fundamental threat to the dairy industry in many countries. A better understanding of the relative importance of within- and between-herd sources of new herd infections coupled with the spatiotemporal distribution of the infection, may aid in effective targeting of control efforts. Thus, the objectives of this study were: (1) to describe the spatiotemporal patterns of infection with S. agalactiae in the population of Danish dairy herds from 2000 to 2009 and (2) to estimate the annual herd-level baseline and movement-related incidence risks of S. agalactiae infection over the 10-year period. The analysis involved registry data on bacteriological culture of all bulk tank milk samples collected as part of the mandatory Danish S. agalactiae surveillance scheme as well as live cattle movements into dairy herds during the specified 10-year period. The results indicated that the predicted risk of a herd becoming infected with S. agalactiae varied spatiotemporally; the risk being more homogeneous and higher in the period after 2005. Additionally, the annual baseline risks yielded significant yet distinctive patterns before and after 2005 - the risk of infection being higher in the latter phase. On the contrary, the annual movement-related risks revealed a non-significant pattern over the 10-year period. There was neither evidence for spatial clustering of cases relative to the population of herds at risk nor spatial dependency between herds. Nevertheless, the results signal a need to beef up within-herd biosecurity in order to reduce the risk of new herd infections.

Temporal characterisation of the network of Danish cattle movements and its implication for disease control: 2000-2009.

Social network analysis provides a valuable framework for understanding the dynamics of diseases on networks as well as a means for defining effective control measures. An understanding of the underlying contact pattern for a susceptible population is advisable before embarking on any strategy for disease control. The objective of this study was to characterise the network of Danish cattle movements over a 10-year period from 2000 to 2009 with a view to understanding: (1) cohesiveness of the network, (2) influential holdings and (3) structural vulnerability of the network. Network analyses of data involving all cattle movements in Denmark registered during the period of interest were performed. A total of 50,494 premises participated in 4,204,895 individual movements during the 10-year period. The results pointed to a predominantly scale-free structure of the network; though marked by small-world properties in March-April 2001 as well as in 24 other months during the period October 2006 to December 2009. The network was sparsely connected with markets being the key influential holdings. Its vulnerability to removal of markets suggests that targeting highly connected holdings during epidemics should be the focus of control efforts.

Evaluation of two herd-level diagnostic tests for Streptococcus agalactiae using a latent class approach.

Streptococcus agalactiae mastitis persists as a significant economic problem for the dairy industry in many countries. In Denmark, the annual surveillance programme for this mastitis pathogen initially based only on bacteriological culture of bulk tank milk (BTM) samples, has recently incorporated the use of the real-time PathoProof Mastitis PCR assay with the goal of improving detection of infected herds. The objective of our study was to estimate the herd sensitivity (Se) and specificity (Sp) of both tests of BTM samples using latent class models in a Bayesian analysis while evaluating the effect of herd-level covariates on the Se and Sp of the tests. BTM samples were collected from all 4258 Danish dairy herds in 2009 and screened for the presence of S. agalactiae using both tests. The highest Se of PCR was realized at a cycle threshold (Ct) cut-off value of 40. At this cut-off, the Se of the PCR was significantly higher (95.2; 95% posterior credibility interval [PCI] [88.2; 99.8]) than that of bacteriological culture (68.0; 95% PCI [55.1; 90.0]). However, culture had higher Sp (99.7; 95% PCI [99.3; 100.0]) compared to PCR (98.8; 95% PCI [97.2; 99.9]). The accuracy of the tests was unaffected by the herd-level covariates. We propose that screenings of BTM samples for S. agalactiae be based on the PCR assay with Ct readings of <40 considered as positive. However, for higher Ct values, confirmation of PCR test positive herds by bacteriological culture is advisable especially when the between-herd prevalence of S. agalactiae is low.

Annual incidence, prevalence and transmission characteristics of Streptococcus agalactiae in Danish dairy herds.

Contagious mastitis pathogens continue to pose an economic threat to the dairy industry. An understanding of their frequency and transmission dynamics is central to evaluating the effectiveness of control programmes. The objectives of this study were twofold: (1) to estimate the annual herd-level incidence rates and apparent prevalences of Streptococcus agalactiae (S. agalactiae) in the population of Danish dairy cattle herds over a 10-year period from 2000 to 2009 inclusive and (2) to estimate the herd-level entry and exit rates (demographic parameters), the transmission parameter, ß, and recovery rate for S. agalactiae infection. Data covering the specified period, on bacteriological culture of all bulk tank milk samples collected annually as part of the mandatory Danish S. agalactiae surveillance scheme, were extracted from the Danish Cattle Database and subsequently analysed. There was an increasing trend in both the incidence and prevalence of S. agalactiae over the study period. Per 100 herd-years the value of ß was 54.1 (95% confidence interval [CI] 46.0-63.7); entry rate 0.3 (95% CI 0.2-0.4); infection-related exit rate 7.1 (95% CI 5.6-8.9); non-infection related exit rate 9.2 (95% CI 7.4-11.5) and recovery rate 40.0 (95% CI 36.8-43.5). This study demonstrates a need to tighten the current controls against S. agalactiae in order to lower its incidence.