Multiplex paper-based designs for point-of-care (POC) diagnostics

Background: Accurate and timely diagnosis is usually the first step towards appropriate disease management. In resource-limited settings, healthcare workers lack proper facilities to perform vital tests, and the diagnosis of disease is often determined by non-specific, physiological symptoms alone. Simple and rapid tests are needed as prerequisite tools for patient care and must conform to the criteria set out by the World Health Organization. To address the challenge of specific diagnosis for diseases that present with similar symptoms, multiplex diagnostic platforms must be designed.Methods: Simple designs for multiplexed paper-based diagnostic platforms were developed. Laser cutting and wax printing were used to create specific patterns on paper to guide the flow of sample and reagents towards reaction zones. Multi-arm and single strip multiplex platforms were designed and tested using Human Immunoglobulin G, Hepatitis B virus surface antigen (HBsAg), and Helicobacter pylori antigens.Results: All designs produced promising results with the lowest limit of detection for antigens being 30ng/ml for single strip designs.Conclusions: The use of glass fibre conjugate pad was found to be more sensitive compared wax-printed chromatography paper. Results from this study indicate great potential for further application in development of diagnostic low-cost paper-based diagnostic devices

Seroprevalence of bovine paratuberculosis in Arusha, Northern Tanzania

Research Article published by American Journal of Research Communication Vol 2(10)Bovine paratuberculosis or Johne’s disease is chronic, contagious granulomatous enteritis of cattle which is caused by Mycobacterium avium subspecies Paratuberculosis (MAP). The disease was first reported in Tanzania in two farms located in Kilimanjaro region in 1960. Despite of quarantine measures that were instituted in the area between 1960-1963, additional cases were reported in Arusha (1976), Mpwapwa (1984), Morogoro (1994). The disease was last reported in the country more than 14 years ago at Kitulo dairy farm in Mbeya region. The paucity of cases has created an impression that the disease is absent from the country. However, the well-known persistence of (MAP) once introduced in the area suggests that the disease may still be present and spreading unnoticed in the country. To obtain information on current state of bovine paratuberculosis, a seroprevalence of the disease in cattle was conducted on bovine serum samples kept in the repository at the Arusha Tanzania Veterinary Laboratory Agency. A total of 207 bovine sera that were collected from urban and peri-urban Arusha as part of contagious bovine pleuropneumonia surveillance in 2011 were tested for MAP-pecific antibodies using the commercial ELISA. The overall seroprevalence was 5.3% (95% CI: 2.3 to 8.4%). These results confirm presence of bovine paratuberculosis in Arusha and indicate the disease may be prevalent in other parts of the country. This is the first seroprevalence report for paratuberculosis in Tanzania

Immunochromatographic thread-based test platform for diagnosis of infectious diseases

This research article published by Springer Nature Switzerland AG., 2018Patterning is an important step in fabrication of multiplexed microfluidic devices. Various approaches including cutting, photolithography, wax-printing, plotting and etching have been developed and tested. Recently, using threads has emerged as a convenient and low-cost approach for fabrication of microfluidic devices. We explored the application of threads in combination with nitrocellulose membrane to fabricate multi-channel immunochromatographic diagnostic devices. Microfluidic channels were made using hydrophilic threads and nitrocellulose membrane strips. Household sewing needle was used to weave hydrophilic thread into desired patterns through a double-sided mounting tape. Glass fibre discs were used as conjugate pads while nitrocellulose membrane was used for immobilisation of capture antibodies. Patterned threads were linked to nitrocellulose membrane strips by overlapping so that reagents flowing through threads were eventually transferred to the membrane. The design was tested using IgG, H. pylori and Hepatitis B surface antigen. Continuous flow was observed from hydrophilic threads to the nitrocellulose membrane, and a positive signal was visualised on the membrane within 5 min of sample application. The observed limit of detection ranged between 30 and 300 ng/ml for H. pylori and Hepatitis B, respectively. Using thread and tape offers a promising alternative for patterning of simple, low-cost multiplexed microfluidic diagnostic devices with potential point-of-care applications in resource-limited settings

Association of Chicken Mx1 Polymorphisms with Susceptibility in Chicken Embryos Challenged with Virulent Newcastle Disease Virus

This research article published by Science Alert, 2020Background and Objective: Genetic selection of chicken genotypes that are less susceptible to Newcastle disease virus (NDV) is a promising option. The present study aimed to investigate polymorphism of chicken Mx1 gene G2032A SNP in different chicken breeds in Tanzania and association with chicken embryos susceptibility to virulent NDV. Materials and Methods: A total of 355 (87 Sasso, 129 Kuroiler and 139 local) 16 days old chicken embryos were infected with 0.1 mL minimum lethal dose (103/0.1 mL) of virulent NDV suspension. The time of death was recorded and selective genotyping was deployed where chicken embryos from high (15%) and less (15%) susceptible cohorts were genotyped by PCR-length polymorphism. Two forward and a reverse primers were used to generate 2 different sizes of PCR product of A and G alleles of chicken Mx1 gene G2032A SNP. Results: As expected chicken embryos survival was highly variable within a breed. The frequency of allele A was higher than allele G in chicken breeds. Furthermore, using Pearson’s X2 test of independence, it was demonstrated that chicken Mx1 gene G2032A genotypes (AA, AG and GG) were associated (p<0.05) with chicken embryos susceptibility to virulent NDV infection. The frequency of genotype AA was higher in less susceptible chicken embryos, whereas, frequency of genotype GG and AG was higher in high susceptible chicken embryos. Conclusion: Results from the present study provide valuable information on the potential role of Mx1 gene polymorphism for selection of chickens that are resistant to virulent NDV infection

Immune response following Newcastle disease immunization and growth performance of kuroiler, broiler and local Tanzanian chickens

This research article was published by Academic Journals in 2020Chicken is a major livestock species raised by smallholder households in rural areas in developing countries of Sub-Saharan Africa as a chief source of meat protein and income generation. However, Newcastle disease largely compromises the production of this precious bird under backyard production settings. The purpose of the study was to assess antibody responses and growth performance following Newcastle disease vaccination in kuroiler, broiler, and local Tanzanian chickens raised under the same tropical environmental condition. In the experiment, a total of 358 chickens comprised of 127 kuroilers, 121 broilers, and 110 local Tanzanian chickens were raised for seven weeks, and body weights were recorded weekly. Birds were vaccinated at four weeks, and blood samples were collected at days 10, and 21 post-vaccination for antibody titres quantification by ELISA test. Results demonstrated higher (P < 0.05) antibody titres in kuroilers (3.81 ± 0.06) as compared to local chicken (3.73 ± 0.07) and broilers (3.53±0.06) at day 10 post-vaccination. The growth performance of local Tanzanian chickens was comparable to that of kuroilers. The present findings contribute to on-going work in understanding chicken immune responses against NDV and inform breeding programs designed for developing chickens with increased resistance to NDV

Colorectal Cancer Epidemiology in Tanzania: Patterns in Relation to Dietary and Lifestyle Factors

This research article was published by American Society of Clinical Oncology in 2018Background: Chronic noncommunicable diseases are increasingly captured as contributing to morbidity and mortality in low and middle income countries. Aim: This study aimed to investigate the epidemiology of colorectal cancer and the potential modifiable local risk factors in Tanzania. Methods: A cross sectional retrospective chart audit study was conducted to establish the pattern and distribution of colorectal cancer, The Food Frequency Questionnaire and the Step® survey tool were used to collect data. Descriptive statistics, χ2 tests, and regression analysis were used and augmented by data visualization to display risk variable differences. Results: Tanzania's colorectal cancer incidence has increased six times in the last decade in which major towns and cities of Dar es Salaam (20.2 per 100,000), Pwani (7.2 per 100,000), Kilimanjaro (4.4 per 100,000), Arusha (4.2 per 100,000), and Morogoro (3.6 per 100,000) had the highest percentage. This study reported that, almost 45% of the participants were hypertensive. Two major dietary patterns, namely “healthy” and “western”, existed among the study sample. Obesity was found in 25% of participants, whereas overweight was present in 28%; of note, the prevalence was higher in females (26.9%) than in males (23.6%) respectively. The prevalence of alcohol consumption was 21.5%, with a significantly lower rate of smoking (12.2%) noted within the study subjects. Both alcohol consumption and tobacco smoking were more common in men than women (22.7 vs. 20.6% and 24.5 vs. 3.2%, respectively). The prevalence of vigorous, moderate, and low physical activity for both sexes was 18.6%, 54.1% and 42.3%, respectively. Conclusion: Evidence from this study demonstrate that, like other NCDs CRC is increasing in Tanzania. Colon cancer is increasing at higher rate than rectal cancer seeming to align with change in lifestyle. Major towns and cities had the highest share of CRC patients. Diet, obesity, tobacco smoking, alcohol consumption, and sedentary behavior have potential role to play in the rising trend of CRC and other NCDs. We recommend a large longitudinal study with robust methodology which can establish cause and effect relationships between specific lifestyle behaviors and the incidence of colorectal cancer

Advancing the development and implementation of regional, national tuberculosis control programs in livestock in Africa, Asia, and Latin America

This research article was published by Frontiers in Veterinary Science in 2023Tuberculosis in livestock caused by members of the Mycobacterium tuberculosis (MTb) complex is a notifiable zoonotic animal disease (1), which has been eradicated or held to very low prevalence levels in many high-income economies. Successful campaigns were all build on a very strict test-and-slaughter strategy using the tuberculin PPD skin tests as diagnostic tool. However, tuberculosis in livestock remains endemic in most Low- and Middle-Income Countries (LMICs). This not only represents a threat to public health in those countries but also places a significant burden on their economies due to a negative impact on livestock productivity and the resources invested in healthcare, prevention, surveillance, and, when present, control and/or eradication programs. Moreover, tuberculosis in livestock affects a wide variety of species as well as breeds, raised in a wide variety of farming systems, in a broad range of different climates, thus ruling out a “one size fits all” approach for disease control. Since “traditional” test and cull programs are costly, very demanding on the livestock holder and may be ruled out as option for religious reasons, such programs must be tailored to ensure they are fit for purpose considering the respective socio-economic context in which they have to be implemented in each country

Maternal, Newborn and Child Health Needs, Opportunities and Preferred Futures in Arusha and Ngorongoro: Hearing women's Voices.

With the approaching sunset on the Millennium Development Goals (MDGs), Tanzania continues with its final national push towards achievement of MDG #4 and MDG #5. The Mama Kwanza Socio-economic Health Initiative (MKSHI) was introduced in the hope of contributing to improving maternal, newborn, and child health in Arusha and Ngorongoro. The MKSHI project is a holistic, inter-sectoral approach to maternal, newborn, and child health which aligns with the Government of Tanzania's Vision 2025. At the project onset, a baseline assessment was conducted to launch ongoing benchmarking, monitoring, and evaluation of the project's impacts and implications. The aim of this baseline assessment was twofold. First it was to determine the state of maternal, newborn, and child health in the two project sites. Second it was to ensure that a baseline of key indicators was established as well as identification of unique indicators relevant to the populations of interest. The baseline study was a mixed methods approach to identify maternal, newborn, and child risk factors and indicators in the two target sites. This paper focuses on the qualitative methods and findings. The qualitative component included a series of five community dialogue meetings and thirty-seven individual/dyad interviews with women, providers, and stakeholders. Initially, community meetings were held as open dialogues on maternal, newborn, and child health issues, opportunities, and preferred futures. Individual/dyad interviews were held with women, providers, and stakeholders who held unique information or experiences. Both community dialogue and interview data was analysed for themes and guiding or critical comments. Three over-arching findings emerged: What took you so long to come? How do we know what you know? and How will it change for our daughters? Participant voices are vital in ensuring the achievement of local and global efforts and preferred futures for maternal, newborn, and child health services. This study contributes to the inclusion of women in all aspects of the planning, implementation, and delivery of maternal, newborn, and child health services in the target areas and beyond

Integrating serological and genetic data to quantify cross-species transmission: brucellosis as a case study

Epidemiological data are often fragmented, partial, and/or ambiguous and unable to yield the desired level of understanding of infectious disease dynamics to adequately inform control measures. Here, we show how the information contained in widely available serology data can be enhanced by integration with less common type-specific data, to improve the understanding of the transmission dynamics of complex multi-species pathogens and host communities. Using brucellosis in Northern Tanzania as a case-study, we developed a latent process model based on serology data obtained from the field, to reconstruct Brucella transmission dynamics. We were able to identify sheep and goats as a more likely source of human and animal infection than cattle; however, the highly cross-reactive nature of Brucella spp. meant that it was not possible to determine which Brucella species (B. abortus or B. melitensis) is responsible for human infection. We extended our model to integrate simulated serology and typing data, and show that although serology alone can identify the host source of human infection under certain restrictive conditions, the integration of even small amounts (5%) of typing data can improve understanding of complex epidemiological dynamics. We show that data integration will often be essential when more than one pathogen is present and when the distinction between exposed and infectious individuals is not clear from serology data. With increasing epidemiological complexity, serology data become less informative. However, we show how this weakness can be mitigated by integrating such data with typing data, thereby enhancing the inference from these data and improving understanding of the underlying dynamics

Factors associated with infectious bursal disease vaccination failure in Dar es salaam, Tanzania

This research article Journal of Veterinary Medicine and Animal Health, Vol. 12(3), July-September 2020Infectious bursal disease (IBD) is a viral infection that affects young chicks. The IBD outbreaks in vaccinated chickens are reported in Tanzania frequently. The current study was conducted to find out the possible causes of vaccination failure focusing on knowledge and practices of vaccine sellers and users, the immunogenic potential of currently used vaccine and the phylogenetic relationship between the vaccine and the field strains. A cross-sectional study was performed to gather information on knowledge and practices from 384 poultry farmers and 20 veterinary outlets in Dar es Salaam. Results revealed inadequate knowledge of farmers in vaccine handling and administration and also breaches in the cold chain maintenance by vaccine sellers was apparent. A total of 60 chicks were experimentally vaccinated with Virgo 7 strain vaccine and titers of induced antibodies assessed. The vaccine induced adequate antibodies against IBDV, confirming its immunogenic efficacy. Isolated nucleic acids from the vaccine and field strains were sequenced and result shows that IBDV field isolates, are genetically different from the vaccine strains used in the country. The field isolates belong to the vvIBDV African types, while the vaccines belong to the vvIBDV European/Asian or classical virulent types. Putting together results from this study reveals multiple possible reasons which may contribute to vaccine failures. These include poor vaccine handling by farmers and vaccine sellers and the genetic disparity between the field and vaccine strains. It is therefore recommended that veterinary regulatory authorities should ensure good vaccine handling practices and considering local virus isolates during vaccine development