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"Mwita, Chacha"
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Aquaculture spillage: a gateway to establishment and colonization of non-indigenous tilapias (Pisces, Cichlidae) in the Pangani Catchment, northern Tanzania
by
Mwita, Chacha J.
,
Chuhila, Yeremia J.
,
Chibwana, Fred D.
in
Aquaculture
,
Aquaculture facilities
,
Biodiversity
2024
The human-mediated transfers of tilapia for aquaculture as a panacea for food insecurity in Africa have led to unprecedented and irreversible impacts on native ichthyofaunal biodiversity. Though aquaculture has been pointed to as the main gateway to species introductions in the Pangani system, formal documentation on how it has contributed to such colonization is anecdotal. The present study aimed to genetically identify, update the list of introduced tilapia taxa, and authenticate if aquaculture is the main gateway to their widespread. We genetically identified non-native tilapias from the Pangani Catchment and aquaculture facilities by genotyping partial Mitochondrial DNA Control region. Molecular analyses depicted the Pangani Catchment to be exclusively inhabited by six non-native tilapiine taxa, particularly
Oreochromis niloticus
,
Oreochromis leucostictus
,
Coptodon rendalli
,
Oreochromis esculentus
,
Oreochromis spilurus
, and
Oreochromis urolepis hornorum
.
Oreochromis niloticus
,
O. leucostictus
, and
C. rendalli
were also predominant in aquaculture and shared haplotypes with their counterparts from the Pangani Catchment. We identified commercial strains of
O. niloticus
that also shared haplotypes between the two systems. Such haplotype sharing proves aquaculture is the gateway to introducing non-native tilapias into the Pangani Catchment. Thus, fish farming in the region should adhere to regional and international legislation to prevent future spillage.
Journal Article
Genotype distribution of human papillomavirus among women with cervical cancer stratified by HIV status in Tanzania
by
Ngoma, Mamsau
,
Rugengamizi, Eulade
,
Samwel, Kandali
in
Adolescent
,
Adult
,
Biology and Life Sciences
2025
Cervical cancer (CC) is the leading cancer among women in Tanzania, especially among those between the ages of 15 and 44. The prevalence of high-risk Human papillomavirus (HR-HPV)-16/18 women in the general population at any given time is 3.3%. HR-HPVs 16 or 18 are the primary cause of CC. The distribution of HPV genotypes among women with CC according to HIV status is unknown in Tanzania. This study aimed to determine the HPV genotype distribution according to HIV status among women with CC in Tanzania.
This cross-sectional study was done at Ocean Road Cancer Institute (ORCI) in Tanzania among women with histologically confirmed CC. HIV serology testing was performed. Biopsy was taken from cervical lesions, and DNA was extracted. HPV DNA was amplified by using a previously validated multiplex HPV PCR assay targeting 14 high-risk HPV genotypes (16,18,30,31,33, 35, 39, 45, 51, 52, 56, 58, 59, and 66) and two low-risk HPV genotypes (6 and 11). Continuous variables were compared using either a student t-test or the Mann-Whitney U test. Fisher's exact test was employed to compare discrete variables. A P-value less than 0.05 was considered statistically significant.
We included 100 women with CC. The prevalence of HIV infection in this study was 42%. The prevalence of any HPV infection was 94%, ranging from 1-3 genotypes per woman. HPV. The median age for women living with HIV (WLWH) with CC patients was 45 years (IQR, 31-60), while the median age for HIV-uninfected women with CC patients was 57 years (IQR, 30-78). (p = 0.0001). WLWH and HIV-uninfected women had similar HPV prevalence, except for HPV 35, which was more common in WLWH. There was a trend of high prevalence of HPV 52 and HPV 58 in WLHH compared to HIV-uninfected women, but this difference was not statistically significant. The prevalence of HPV 16 and/or 18 infection in the entire sample was 85%. The combined prevalence of HPV 16 and/or 18 was 76% WLWH and 91% amongst HIV-uninfected women (p = 0.036).The majority of women (77.9%) had single-genotype HPV infection. There was no difference in the distribution of multiple or single HPV genotypes infection by HIV status (p = 0.25).
In this study, HIV positive women with CC presented at a significantly younger age (45 years) compared to the HIV-negative women (57 years). The prevalence of high-risk HPV is high among women with CC in Tanzania. Distribution of most high-risk HPV genotypes among women with CC was not significantly influenced by HIV status except for HPV 35, which appeared to be more in HIV positive women compared to HIV-negative women. While the majority of the high-risk HPV infections were with single HPV genotypes, the prevalence of multiple high-risk HPV infections was at 22%, with no significant difference between the two HIV statuses. A vaccination program that aptly targets HPV 16 and 18 could prevent up to 85% of CC cases in Tanzania, regardless of HIV. Keywords: Human papillomavirus, cervical cancer, HIV, Tanzania.
Journal Article
Colonial ties and civil conflict intervention
2019
Civil war intervention literature identifies colonial history as influencing the likelihood of interventions. This literature, however, has yet to clarify the mechanisms through which colonial history influences interventions. We develop and test an argument linking the relations established by colonialism—economic, political, and social—with interventions. We find that colonial history influences interventions, but its effect matters less once we control for these three relations. Importantly, we find that this effect of colonial history is particularly small in dyads with stronger economic relations. Our paper gives further credence to liberal arguments emphasizing the role of economic factors in international security.
Journal Article
Viral Epitope Scanning Reveals Correlation between Seasonal HCoVs and SARS-CoV-2 Antibody Responses among Cancer and Non-Cancer Patients
by
Bennett, Sydney J.
,
Ngalamika, Owen
,
West, John T.
in
Acquired immune deficiency syndrome
,
AIDS
,
Antibodies
2024
Seasonal coronaviruses (HCoVs) are known to contribute to cross-reactive antibody (Ab) responses against SARS-CoV-2. While these responses are predictable due to the high homology between SARS-CoV-2 and other CoVs, the impact of these responses on susceptibility to SARS-CoV-2 infection in cancer patients is unclear. To investigate the influence of prior HCoV infection on anti-SARS-CoV-2 Ab responses among COVID-19 asymptomatic individuals with cancer and controls without cancers, we utilized the VirScan technology in which phage immunoprecipitation and sequencing (PhIP-seq) of longitudinal plasma samples was performed to investigate high-resolution (i.e., epitope level) humoral CoV responses. Despite testing positive for anti-SARS-CoV-2 Ab in the plasma, a majority of the participants were asymptomatic for COVID-19 with no prior history of COVID-19 diagnosis. Although the magnitudes of the anti-SARS-CoV-2 Ab responses were lower in individuals with Kaposi sarcoma (KS) compared to non-KS cancer individuals and those without cancer, the HCoV Ab repertoire was similar between individuals with and without cancer independent of age, sex, HIV status, and chemotherapy. The magnitudes of the anti-spike HCoV responses showed a strong positive association with those of the anti-SARS-CoV-2 spike in cancer patients, and only a weak association in non-cancer patients, suggesting that prior infection with HCoVs might play a role in limiting SARS-CoV-2 infection and COVID-19 disease severity.
Journal Article
The contribution of milkfish (Chanos chanos) pond farming to socio-economics and coastal community livelihoods for a sustainable blue economy in Tanzania
by
Shalli, Mwanahija S.
,
Jiddawi, Narriman S.
,
Mapenzi, Levinus L.
in
Agricultural economics
,
Agriculture
,
Biological fertilization
2024
The knowledge of socio-economics and livelihoods of milkfish (
Chanos chanos
) pond farming to coastal communities is limited in Tanzania. This study assessed the milkfish pond farming contribution to the socio-economics and livelihoods along the Tanzanian coastline. Sixty-three milkfish farms were interviewed through a semi-structured questionnaire. The results indicated that milkfish pond farming was characterized by low production. The milkfish pond production was positively influenced by farmers’ experience, the number of fingerlings stocked, and pond fertilization. However, milkfish pond farming was significantly negatively affected by days of culture and age of the farmers. The results further showed that milkfish pond farming is a source of income to the owners after selling their fish through retail, wholesale, and on-farm sales via mobile phone communications. However, milkfish pond farms in the studied areas had a negative margin considering all financial factors. Interestingly, milkfish pond farming is a source of food, income, and employment to the community. Nevertheless, milkfish pond farming is constrained by inadequate feeds, seeds, funds, technical support, and existence of theft and predators. Therefore, addressing these challenges is necessary for enhancing milkfish pond farming contribution to the socio-economics well-being and livelihoods support for the coastal communities.
Journal Article
Testing the performance of environmental DNA metabarcoding for surveying highly diverse tropical fish communities: A case study from Lake Tanganyika
by
Murrell, David J.
,
Mwita, Chacha
,
Day, Julia J.
in
cichlids
,
environmental DNA
,
Lake Tanganyika
2020
Background and Aims Environmental DNA (eDNA) metabarcoding provides a highly sensitive method of surveying freshwater fish communities, although studies to date have largely been restricted to temperate ecosystems. Due to limited reference sequence availability and challenges identifying closely related and rare species in diverse tropical ecosystems, the effectiveness of metabarcoding methods for surveying tropical fish communities from eDNA samples remains uncertain. To address this, we applied an eDNA metabarcoding approach to survey Lake Tanganyika's (LT) species‐rich littoral fish communities. Materials and Methods As this system contains many closely related species, particularly cichlid fishes, we used four primer sets including a cichlid‐specific primer set (Cichlid_CR). A reference database was built for the 12s, 16s, and control region for 358 fish species including over 93% of known cichlids. Results and Discussion In silico and in situ results demonstrated wide variability in the taxonomic resolution of assignments by each primer with the cichlid‐specific marker (Cichlid_CR) enabling greater species‐level assignments for this highly diverse family. A greater number of non‐cichlid teleost species were detected at sites compared to the visual survey data. For cichlid species however, sequencing depth substantially influenced species richness estimates obtained from eDNA samples, with increased depths producing estimates comparable to that obtained from the visual survey data. Conclusions Our study highlights the importance of sequencing depth and local reference databases when undertaking metabarcoding studies within diverse ecosystems, as well as demonstrating the potential of eDNA metabarcoding for surveying diverse tropical fish communities, even those containing closely related species within evolutionary radiations. This study applies an environmental DNA metabarcoding methodology for surveying Lake Tanganyika’s highly diverse littoral fish communities. The results highlight the importance of sequencing depth and local reference database completeness when undertaking metabarcoding studies within diverse ecosystems, as well as demonstrating the potential of eDNA metabarcoding for surveying diverse tropical fish communities, even those containing closely related species within evolutionary radiations.
Journal Article
Cage‐Cultured Nile Tilapia (Oreochromis niloticus) Farming: A Third Generation of Pollution in Lake Victoria, Tanzania
by
Kimaro, Esther G.
,
Komba, Richard S.
,
Mwita, Chacha J.
in
cage fish farming
,
Lake Victoria
,
Nile tilapia
2025
This study was carried out along the Mwanza Gulf, Lake Victoria, Tanzania, where water samples for the determination of physico‐chemical parameters were collected from March to October 2023. NH4+‐N, NO3−‐N, NO2−‐N, and PO4+‐P were analyzed using standard methods. Temperature (°C), electrical conductivity (µS/cm), dissolved oxygen (mg/L), pH, and turbidity were measured in situ. Water temperature ranged from 27.9°C at Misungwi to 29.1°C at Nyamagana. Dissolved oxygen (DO) was high at Ilemela (6.70 mg/L) and declined (5.78 mg/L) at Nyamagana. Electrical conductivity and water turbidity increased as the number of cages sampled increased. Nitrate increased from 0.09 mg/L (90 µg/L) at Ilemela to 0.15 mg/L (150 µg/L) at Nyamagana, ammonia concentration from 0.26 mg/L (260 µg/L) to 0.45 mg/L (450 µg/L) at Nyamagana, and phosphate increased from 0.26 mg/L (260 µg/L) to 1.41 mg/L (1410 µg/L). When the results of this study were compared to those reported before 2015, the variations were significant at all levels. We conclude that inputs from cage fish farming are contributing immensely to nutrients loading and thus pollution in the lake. The riparian governments around the lake are urged to take measures that will ensure sustainable cage fish farming without jeopardizing the environmental quality of Lake Victoria with the consequential collapse of the existing fishery.
Journal Article
Closing the Book on Africa's First Generation Coups
by
Powell, Jonathan
,
Chacha, Mwita
in
Analysis
,
Appointments, resignations and dismissals
,
Armed forces
2019
The Zimbabwe Defence Forces' November 2017 removal of Robert Mugabe was the first successful military coup in Africa in over three years. Increasingly rare in contemporary politics, Mugabe's removal at the barrel of the gun was a common fate for the original generation of political leadership in the region. We contextualize Mugabe's removal by reviewing the fates of Sub-Saharan Africa's original post-colonial leadership, of which a majority was directly removed in military coups. The fall of Mugabe can be seen as the final chapter on coups against the original generation of leadership, but is unique in regard to the fate of the ousted leader. Of all prior first generation leaders removed via a coup, each was imprisoned, exiled, or killed in association with the coup.
Journal Article
Chitosan Extracted from the Biomass of Tenebrio molitor Larvae as a Sustainable Packaging Film
2024
Waste from non-degradable packaging materials poses a serious environmental risk and has led to interest in developing sustainable bio-based packaging materials. Sustainable packaging materials have been made from diverse naturally derived materials such as bamboo, sugarcane, and corn starch. In this study, we made a sustainable packaging film using chitosan extracted from the biomass of yellow mealworm (Tenebrio molitor) shell waste. The extracted chitosan was used to create films, cross-linked with citric acid (CA) and with the addition of glycerol to impart flexibility, using the solvent casting method. The successful cross-linking was evaluated using Fourier-Transform Infrared (FTIR) analysis. The CA cross-linked mealworm chitosan (CAMC) films exhibited improved water resistance with moisture content reduced from 19.9 to 14.5%. Improved barrier properties were also noted, with a 28.7% and 10.2% decrease in vapor permeability and vapor transmission rate, respectively. Bananas were selected for food preservation, and significant changes were observed over a duration of 10 days. Compared to the control sample, bananas packaged in CAMC pouches exhibited a lesser loss in weight because of excellent barrier properties against water vapor. Moreover, the quality and texture of bananas packaged in CAMC pouch remained intact over the duration of the experiment. This indicates that adding citric acid and glycerol to the chitosan structure holds promise for effective food wrapping and contributes to the enhancement of banana shelf life. Through this study, we concluded that chitosan film derived from mealworm biomass has potential as a valuable resource for sustainable packaging solutions, promoting the adoption of environmentally friendly practices in the food industry.
Journal Article