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

Review of the Current Status on Livestock Abortigenic Diseases Surveillance in Africa and Asia

This article was published in the Journals Sustainability Volume 16, Issue 5, 2024Introduction: Livestock abortigenic agents, which are microorganisms that lead to premature foetal death and expulsion before completion of the gestation period, are common in Africa and Asia. Abortion events cause economic losses by lowering reproduction (and hence herd/flock sizes) and effects on milk production. Despite the importance of livestock production for food security and livelihoods of millions of the world’s poorest communities, very little is known about the scale, magnitude or causes of livestock abortion in Africa. The aim of this review was to determine the current status of the burden of livestock abortion and surveillance measures adopted for livestock abortigenic pathogens in Africa and Asia, and to explore feasible surveillance technologies. Methodology: A systematic literature search was conducted using Preferred Reporting of Systematic Reviews and Meta-analyses (PRISMA) guidelines in four databases for studies published between 1 Jan 1990 and 31 July 2021 that reported epidemiological surveys of livestock abortigenic pathogens in cattle, goats and sheep in Africa and Asia including; Brucella spp., Neospora caninum, Toxoplasma gondii, Rift valley fever virus, Coxiella burnetii, Chlamydia, Leptospira and Bovine viral Diarrhoea Virus. A meta-analysis was used to estimate the species-specific prevalence of the abortigenic diseases and the region where they were detected. Results: In the systematic literature search, 48 full papers were included which in total included 50 species-specific surveillance reports from Africa and 19 from Asia. Adjusted median seroprevalence calculations estimated Brucella at 6.85% (range 1.2-11.6) of 9071 sheep, 3.35% (range 0.90-5.40) of 17,007 goats, 8.95% (range 0.50-63.60) of 171,733 cattle, Neospora at 6.80% (range 6.80 -6.80) of 555 sheep, 10.80 (range 10.80-10.80) of 185 goats, 12.65% (range 3.40- 25.60) of 3775 cattle, Toxoplasma at 27.50% (range 1.40 – 75.90) of 2284 sheep, 32.0% (range 20.00- 64.80) of 1226 goats, 7.50% (range 7.50 - 7.50) of 174 cattle, Coxiella at 9.20 (range 9.20 – 9.20) of 184 sheep, 24.20% (range 24.20-24.20) of 91 goats, 13.80% (range 13.80-13.80) of 217 cattle, Rift valley fever virus at 7.70 (2.40-40.00) of 874 sheep, 20.95 (range 2.50-40.00) of 547 goats, 7.45% (range 3.60-11.30) of 309 cattle, Bovine viral diarrhea virus at 78.90 (range 78.90 – 78.90) of 398 cattle, Leptospira at 70.50 (range 70.50 – 70.50) of 373 cattle and Chlamydia at 6.60 (6.60-6.60) of 803 sheep. We found that most studies, 45 (89%) used serological surveys, 1 (2%) used molecular and 1 (2%) reported to have used Mobile-phone based surveillance approach. Three studies (6.25%) of the 48 included were embedded in the national surveillance programs of the respective countries they were conducted, majority 89% were stand-alone cross- sectional studies. Conclusion :In conclusion, livestock abortigenic pathogens are still a burden in many African and Asian countries

Review of the Current Status on Livestock Abortigenic Diseases Surveillance in Africa and Asia.

This article was published on March 8, 2024, and its Dio is doi:10.20944/preprints202403.0464.v. It is also available at the Nelson Mandela institute repositoryIntroduction: Livestock abortigenic agents, are microorganisms that lead to premature foetal death and expulsion before completion of the gestation period, are common in Africa and Asia. Abortion events cause economic losses by lowering reproduction (and hence herd/flock sizes) and effects on milk production. Despite the importance of livestock production for food security and livelihoods of millions of the world’s poorest communities, very little is known about the scale, magnitude or causes of livestock abortion in Africa. The aim of this review was to determine the current status of the burden of livestock abortion and surveillance measures adopted for livestock abortigenic pathogens in Africa and Asia, and to explore feasible surveillance technologies. Methodology: A systematic literature search was conducted using Preferred Reporting of Systematic Reviews and Meta-analyses (PRISMA) guidelines in four databases for studies published between 1 Jan 1990 and 31 July 2021 that reported epidemiological surveys of livestock abortigenic pathogens in cattle, goats and sheep in Africa and Asia including; Brucella spp., Neospora caninum, Toxoplasma gondii, Rift valley fever virus, Coxiella burnetii, Chlamydia, Leptospira and Bovine viral Diarrhoea Virus. A meta-analysis was used to estimate the species-specific prevalence of the abortigenic diseases and the region where they were detected. Results: In the systematic literature search, 48 full papers were included which in total included 50 species-specific surveillance reports from Africa and 19 from Asia. Adjusted median seroprevalence calculations estimated Brucella at 6.85% (range 1.2-11.6) of 9071 sheep, 3.35% (range 0.90-5.40) of 17,007 goats, 8.95% (range 0.50-63.60) of 171,733 cattle, Neospora at 6.80% (range 6.80 -6.80) of 555 sheep, 10.80 (range 10.80-10.80) of 185 goats, 12.65% (range 3.40- 25.60) of 3775 cattle, Toxoplasma at 27.50% (range 1.40 – 75.90) of 2284 sheep, 32.0% (range 20.00- 64.80) of 1226 goats, 7.50% (range 7.50 - 7.50) of 174 cattle, Coxiella at 9.20 (range 9.20 – 9.20) of 184 sheep, 24.20% (range 24.20-24.20) of 91 goats, 13.80% (range 13.80-13.80) of 217 cattle, Rift valley fever virus at 7.70 (2.40-40.00) of 874 sheep, 20.95 (range 2.50-40.00) of 547 goats, 7.45% (range 3.60-11.30) of 309 cattle, Bovine viral diarrhea virus at 78.90 (range 78.90 – 78.90) of 398 cattle, Leptospira at 70.50 (range 70.50 – 70.50) of 373 cattle and Chlamydia at 6.60 (6.60-6.60) of 803 sheep. We found that in most studies, 45 (89%) used serological surveys, 1 (2%) used molecular and 1 (2%) reported to have used Mobile-phone based surveillance approach. Three studies (6.25%) of the 48 included were embedded in the national surveillance programs of the respective countries they were conducted, the majority 89% were stand-alone cross sectional studies. Conclusion: In conclusion, livestock abortigenic pathogens are still a burden in many African and Asian countries

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

Towards Control of Taenia multiceps, an Emerging Threat to Small Ruminants’ Productivity.

This article was published on February 20 2024, its have Dio which is doi:10.20944/preprints202402.1127.v1and is available at the Nelson Mandela Institute repositoryTaeniid infections pose a significant threat to both animal and public health, as certain tapeworms within this group can also infect humans, potentially leading to severe health conditions. Therefore, this calls for preventive and control measures, such as regular deworming of dogs. While the efficacy of deworming has been established in developed countries, there is a paucity of reported deworming practices in rural areas of developing countries, such as Tanzania. This study aims to understand determinants for helminth treatment-seeking behaviour towards control of custodial taeniid infections in rural settings in northern Tanzania. A cross-sectional study was undertaken in agropastoral and pastoral areas of northern Tanzania. Comprehensive data from household surveys in selected sub-villages were collected to ascertain dog ownership, dog deworming practices, and the availability of dewormers. Analytical methods were employed to discern how various determinants influenced deworming practices among dog owners in these communities. Awareness of dewormers specifically formulated for dogs emerged as a pivotal factor affecting dog deworming practices. Dog owners who were informed about appropriate dog dewormers were nearly two times more likely to engage in deworming compared to those with limited knowledge (OR = 1.78, 95% CI 1.77 - 4.18, p < 0.001). A majority 32(51.6%, 95% CI: 38.7-64.3) acknowledged accessing dewormers for livestock within their wards. Praziquantel a potent dewormer on cestodes was least known to most dog owners 2(13%, 95% CI: 2.3-41.6). Praziquantel, a potent and common dewormer effective against custodial taeniid infections, remains relatively unknown in rural areas of northern Tanzania. Therefore, more awareness of appropriate deworming agents against taeniids in dogs should be raised in rural dog-keeping communities

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

Determinants of Dogs’ Helminth Treatment-Seeking Behavior among Dog Owners in Rural Northern Tanzania: Towards Control of Taenia multiceps, an Emerging Threat to Small Ruminants’ Productivity

A research article was published by Preprints, 2024Taeniid infections pose a significant threat to both animal and public health, as certain tapeworms within this group can also infect humans, potentially leading to severe health conditions. Therefore, this calls for preventive and control measures, such as regular deworming of dogs. While the efficacy of deworming has been established in developed countries, there is a paucity of reported deworming practices in rural areas of developing countries, such as Tanzania. This study aims to understand determinants for helminth treatment-seeking behavior towards control of cestodial taeniid infections in rural settings in northern Tanzania. A cross-sectional study was undertaken in agropastoral and pastoral areas of northern Tanzania. Comprehensive data from household surveys in selected sub-villages were collected to ascertain dog ownership, dog deworming practices, and the availability of dewormers. Analytical methods were employed to discern how various determinants influenced deworming practices among dog owners in these communities. Awareness of dewormers specifically formulated for dogs emerged as a pivotal factor affecting dog deworming practices. Dog owners who were informed about appropriate dog dewormers were nearly two times more likely to engage in deworming compared to those with limited knowledge (OR = 1.78, 95% CI 1.77 - 4.18, p < 0.001). A majority 32(51.6%, 95% CI: 38.7-64.3) acknowledged accessing dewormers for livestock within their wards. Praziquantel a potent dewormer on cestodes was least known to most dog owners 2(13%, 95% CI: 2.3-41.6). Praziquantel, a potent and common dewormer effective against cestodial taeniid infections, remains relatively unknown in rural areas of northern Tanzania. Therefore, more awareness on appropriate deworming agents against taeniids in dogs should be raised in rural dog-keeping communitie

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

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

The Efficacy of Single-Dose versus Double-Dose Praziquantel Treatments on Schistosoma mansoni

Administering more than one treatment may increase Praziquantel cure and egg reduction rates, thereby hastening achievement of schistosomiasis transmission control. A total of 431 S. mansoni-infected schoolchildren were randomized to receive either a single or repeated 40 mg/kg Praziquantel dose. Heights, weights, and haemoglobin levels were determined using a stadiometer, weighing scale, and HemoCue, respectively. At 8 weeks, cure rate was higher on repeated dose (93.10%) compared to single dose (68.68%) (p0.05) and 8 (p>0.05) months with no difference in reinfection rate. No difference in the prevalence of stunting was observed between the two treatment regimens (p>0.05) at 8 months, but there was an increase in the prevalence of wasting among those on repeated dose (p0.05). To achieve reduction of transmission intensity and disease control in highly endemic areas, repeated treatments alone may not be sufficient. This trial was registered with PACTR201601001416338