Levels and distribution of progesterone in receiving waters and wastewaters of a growing urban area.

This study aimed at investigating the levels and distribution of progesterone in receiving waters and wastewaters in Arusha, a fast-growing urban area and the third largest city in Tanzania. Specifically, the study was conducted along the Themi River and the adjacent waste stabilization ponds (WSPs). Progesterone was detected and quantified by using an enzyme-linked immunosorbent assay (ELISA) kit. For Themi River samples, the level of progesterone obtained ranged from 'no detection' to 439 ng/L with a mean value of 120.3 ng/L. The levels detected were significantly higher in the midstream than the upstream and downstream sections of the river (P<0.05). The higher values at the midstream were attributable to livestock, WSPs and household effluents; agricultural activities; and sewage infiltration. Progesterone levels in the present study, although not extremely high, correspond to those associated with harmful effects in other studies. Results for samples collected from the WSPs indicated a release of 215 ng progesterone per L of the receiving waters. Although progesterone removal efficiency by the WSPs was 75%, the amount released was still high enough to cause harm to aquatic organisms. Thus, more efficient techniques are required to adequately remove progesterone to the recommended levels.

Characterization of Salmonella spp. from wastewater used for food production in Morogoro, Tanzania.

Wastewater use for crop irrigation and aquaculture is commonly practiced by communities situated close to wastewater treatment ponds. The objective of this study was to characterize Salmonella spp. and their antimicrobial susceptibility patterns among isolates from wastewater and Tilapia fish. A total of 123 Salmonella spp. isolates were isolated from 52 water and 21 fish intestinal samples. Genotyping of Salmonella spp. isolates was done by Pulsed-field Gel Electrophoresis (PFGE). Antimicrobial susceptibility testing was done by the minimal inhibitory concentration (MIC) technique. A total of 123 Salmonella spp. isolates represented 13 different serovars and 22 PFGE groups. Salmonella serovars showed resistance to 8 out of 14 antimicrobials; sulfamethaxazole (94%), streptomycin (61%), tetracycline (22%), ciprofloxacin and nalidixic acid (17%), trimethoprim (11%); gentamycin and chloramphenicol (6%). Salmonella Kentucky, S. Chandans, S. Durban and S. Kiambu showed multiple antimicrobial resistance to 7, 6 and 3 antimicrobials, respectively. This study has demonstrated that wastewater at the study sites is contaminated with Salmonella spp. which are resistant to common antimicrobials used for treatment of diseases in humans. Wastewater may, therefore, contaminate pristine surface water bodies and foodstuffs including fish and irrigated crops as well as food handlers.

Bioaccumulation and public health implications of trace metals in edible tissues of the crustaceans Scylla serrata and Penaeus monodon from the Tanzanian coast.

The coastal population in East Africa is growing rapidly but sewage treatment and recycling facilities in major cities and towns are poorly developed. Since estuarine mangroves are the main hotspots for pollutants, there is a potential for contaminants to accumulate in edible fauna and threaten public health. This study analysed trace metals in muscle tissues of the giant mud crabs (Scylla serrata) and the giant tiger prawns (Penaeus monodon) from the Tanzanian coast, in order to determine the extent of bioaccumulation and public health risks. A total of 180 samples of muscle tissues of S. serrata and 80 of P. monodon were collected from nine sites along the coast. Both species showed high levels of trace metals in the wet season and significant bioaccumulation of As, Cu and Zn. Due to their burrowing and feeding habits, mud crabs were more contaminated compared to tiger prawns sampled from the same sites. Apart from that, the measured levels of Cd, Cr and Pb did not exceed maximum limits for human consumption. Based on the current trend of fish consumption in Tanzania (7.7 kg/person/year), the measured elements (As, Cd, Co, Cu, Mn, Pb and Zn) are not likely to present health risks to shellfish consumers. Nevertheless, potential risks of As and Cu cannot be ruled out if the average per capita consumption is exceeded. This calls for strengthened waste management systems and pollution control measures.

Epidemiology and RAPD-PCR typing of thermophilic campylobacters from children under five years and chickens in Morogoro Municipality, Tanzania.

BACKGROUND: Campylobacter species are gram negative and flagellated bacteria under the genus Campylobacter, family Campylobacteriaceae. These pathogens cause zoonotic infections among human and animal populations. This study was undertaken between December 2006 and May 2007 to determine prevalence, risk factors and genetic diversity of thermophilic Campylobacter isolates from children less than 5 years and chickens in Morogoro Municipality, Tanzania. METHODS: The Skirrow's protocol was used for isolation and identification of Campylobacter from 268 human stool specimens and 419 chicken cloacal swabs. Patient biodata and risk factors associated with human infection were also collected. Genetic diversity of Campylobacter isolates was determined by a RAPD-PCR technique using OPA 11 primer (5'-CAA TCG CCG T-3'). Phylogenetic analysis and band pattern comparison were done by Bionumerics software and visual inspection. RESULTS: Stool samples from 268 children and 419 cloacal swabs from chickens were analyzed. Prevalence of thermophilic Campylobacters in children was 19% with higher isolation frequency (p = 0.046) in males (23.5%) than females (13.8%). Campylobacter jejuni (78.4%) was more isolated (p = 0.000) than C. coli (19.6%) and 2% were unidentified isolates. In chickens, the prevalence was 42.5% with higher isolation rate (p = 0.000) of C. jejuni (87%) than C. coli (13%). Campylobacters were more frequently recovered (p = 0.000) from indigenous/ local chickens (75.0%) followed by cockerels (52.2%), broilers (50.0%) and lowest in layers (22.7%). Keeping chickens without other domestic animals concurrently (p = 0.000), chicken types (p = 0.000) and flock size (p = 0.007) were risk factors for infection in chickens. One hundred and fifty two (152) thermophillic Campylobacter isolates were genotyped by RAPD-PCR of which 114 were C. jejuni (74 from chickens and 40 humans) and 38 C. coli (28 from chickens and 10 humans). Comparison of Campylobacter isolates from children and chickens revealed high diversity with only 6.1% of C. jejuni and 5.3% of C. coli being 100% genetically similar. CONCLUSIONS: This study has recorded high prevalence of thermophilic Campylobacter in children less than 5 years and chickens in Morogoro municipality. The observed genetic similarity among few C. jejuni and C. coli isolates from children and chicken suggests existence of cross transmission of these pathogens between children under 5 years and chickens.

Trace metals in the giant tiger prawn Penaeus monodon and mangrove sediments of the Tanzania coast: Is there a risk to marine fauna and public health?

Mangroves ecosystems support livelihood and economic activities of coastal communities in the tropics and subtropics. Previous reports have documented the inefficiency of waste treatment facilities in Tanzania to contain trace metals. Therefore, the rapidly expanding coastal population and industrial sector is likely to threaten mangrove ecosystems with metal pollution. This study analysed trace metals in 60 sediment samples and 160 giant tiger prawns from the Tanzanian coast in order to document the distribution of trace metals and to establish if measured levels present a threat to mangrove fauna and are of public health importance. High levels of Cr, Co, Cu, Fe, Mn, Ni, and V was observed in mangroves of river Pangani, Wami, and Rufiji. Multivariate analysis showed that they originate mainly from weathering and erosion in the river catchments. Extreme enrichment of Cd was observed in a mangrove affected by municipal sewage. The distribution of Hg, Pb, and Zn was related with urbanisation and industrial activities along the coast. The metal pollution index was high at Pangani, Saadani, and Rufiji, suggesting that these estuarine mangroves are also affected by human activities in the catchment. Moderate to considerable ecological risks were observed in all sampled mangroves, except for Kilwa Masoko. It was revealed that As, Cd, and Hg present moderate risks to fauna. High levels of Cu, Fe and Zn were observed in prawns but the level of the non-essential Cd, Hg, and Pb did not exceed the maximum allowed levels for human consumption. However, based on the trends of fish consumption in the country, weekly intake of Hg is likely to exceed provisional tolerable weekly intake level, especially in fishing communities. This calls for measures to control Hg emissions and to strengthen sewage and waste treatment in coastal cities and urban centres in the basin of major rivers.

Effect of resinous extract from Commiphora swynnertonii (Burrt) on experimental coccidial infection in chickens.

A crude resinous extract from Commiphora swynnertonii was tested against an experimental coccidial infection in local chickens. A total of 80 growing chickens were randomly assigned into five groups, which received different treatments. Chickens in G1 were not infected with coccidian oocysts and therefore served as a negative control. All chickens in G2, G3, G4 and G5 were infected through oral administration of coccidian oocysts suspension at a dosed rate of 1.5 × 10(4) Eimeria spp. oocysts per bird. Starting from day 3 post-infection (p.i), chickens in different groups were treated for 7 consecutive days as follows: G1 and G2 (positive control) received 5 ml of normal saline as placebo, G3 and G4 were given the extract at 400 and 800 mg/kg bodyweight whereas G5 received anticoccidial drug. Clinical signs, bodyweights, oocysts counts and mortality rates were observed regularly. Results showed that oral administration of the resinous extract to chickens with coccidiosis significantly reduced mortality rate from 94 to 25 % and oocysts counts from 1.03 × 10(5) to 6.55 × 10(3) oocysts/g faeces (p < 0.05). Also a body condition score chart indicated less severe clinical signs of the disease in the groups which received the extract. Mean daily body weights were slightly reduced by the administration of the extract but this effect disappeared by day 7 p.i. These findings clearly indicate that resinous extract from C. swynnertonii has significant anticoccidial effect against experimental Eimeria spp. infection in chickens. A larger field trial to validate the use of the extract in chickens naturally infected with Eimeria spp. is required.

Optimization of HPLC-MS/MS method for determination of antimalarial adulterants in herbal products.

The use of herbal products is booming all over the world because of being believed as safer than conventional drugs and free of side effects. However, there are untrustworthy manufacturers who adulterate herbal products by adding conventional drugs which might eventually lead to microbial resistance and herb-to-drug interactions. There is a need to develop methods for detecting adulterants in herbal products. A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for simultaneous identification and determination of conventional antimalarials (chloroquine, quinine, sulfadoxine, pyrimethamine, mefloquine, lumefantrine, amodiaquine, artemisinin, dihydroartemisinin, artesunate and artemether) in herbal products was developed. Stable isotopically labelled compounds (artemether-d3, quindine-d3, and sulfadoxine-d3) were used as internal standards (ISs) for quantitative analysis. Extraction of analytes was performed using methanol: water: formic acid (90:10:0.1, v/v) and chromatographic separation was done in a gradient mode using mobile phase A: Ultrapure water containing 0.1% formic acid and 1 mM ammonium formate and mobile phase B: Acetonitrile/methanol (50:50) containing 0.1% formic acid and 1 mM ammonium formate. The calibration curves were linear (r2 ≥ 0.991) over the range of 0.001-0.3 µg mL-1 for all compounds. The limit of detection (LOD) ranged from 0.002 to 0.02 µg mL-1 while the limit of quantification (LOQ) ranged from 0.006 to 0.08 µg mL-1. Accuracy, expressed as recovery of spiked herbal products ranged from 52 to 128%. The precision, expressed as percent relative standard deviation (%RSD) at two concentration levels, ranged from 1.0 to 13.8%. The matrix effect expressed as the matrix factor (MF) ranged from 0.77 to 0.97. The developed method was used to identify and quantify conventional antimalarials in herbal product samples from Tanzania. Ten out of 50 herbal products were found to contain amodiaquine, sulfadoxine, pyrimethamine, mefloquine, dihydroartemisinin, artemether and lumefantrine. The developed method is considered a valuable tool for getting a better understanding of the adulteration of conventional antimalarials in herbal products.

Mitigating antimicrobial resistance (AMR) using implementation research: a development funder's approach.

Despite the escalating burden of antimicrobial resistance (AMR), the global response has not sufficiently matched the scale and scope of the issue, especially in low- and middle-income countries (LMICs). While many countries have adopted national action plans to combat AMR, their implementation has lagged due to resource constraints, dysfunctional multisectoral coordination mechanisms and, importantly, an under-recognized lack of technical capacity to adapt evidence-based AMR mitigation interventions to local contexts. AMR interventions should be tailored, context-specific, cost-effective and sustainable. The implementation and subsequent scale-up of these interventions require multidisciplinary intervention-implementation research (IIR). IIR involves both quantitative and qualitative approaches, occurs across a three-phase continuum (proof of concept, proof of implementation and informing scale-up), and across four context domains (inner setting, outer setting, stakeholders and the implementation process). We describe the theoretical underpinnings of implementation research (IR), its various components, and how to construct different IR strategies to facilitate sustainable uptake of AMR interventions. Additionally, we provide real-world examples of AMR strategies and interventions to demonstrate these principles in practice. IR provides a practical framework to implement evidence-based and sustainable AMR mitigation interventions.

Antiviral activity of crude extracts from Commiphora swynnertonii against Newcastle disease virus in ovo.

Studies were carried out to investigate the effect of crude extracts from resin, leaves, stem barks and root barks of Commiphora swynnertonii against Newcastle disease virus (NDV) using an in ovo assay. Nine-day-old embryonated chicken eggs were divided into seven groups (n = 6) and received various treatments. Six groups were inoculated with velogenic NDV strain; five groups out of these were treated with different concentrations of the four extracts or a diluent, dimethylsulphoxide. The uninoculated and inoculated groups were left as negative and positive controls, respectively. Embryo survival was observed daily and embryo weights were measured day 5 post-inoculation; a few eggs from selected groups were left to hatch. Allantoic fluid from treated eggs and serum from hatched chicks were collected for hemagglutination and hemagglutination inhibition (HI) tests to detect NDV in the eggs and antibodies against NDV in the hatched chicks respectively. Results showed that embryo survival and mean embryo weight were significantly higher (p < 0.001) in those groups which were treated with the crude extracts from C. swynnertonii than the positive control group. Also the extracts significantly (p < 0.001) reduced virus titres, whereas no viruses were detected in the allantoic fluids of the resin-treated group at the highest concentration of 500 µg/mL. Furthermore, the HI test results showed very low levels of antibodies against NDV in chicks hatched from resin and root bark extract-treated eggs suggesting that these plant materials were capable of destroying the NDV before stimulating the developing chick's immunity. The current findings have clearly demonstrated that crude extracts especially that of resin from C. swynnertonii have strong antiviral activity against NDV in ovo. In vivo trials are needed to validate the use of resin from the tree in controlling Newcastle disease in chickens.

Comparison of Cape Town and Skirrow's Campylobacter isolation protocols in humans and broilers in Morogoro, Tanzania.

Comparison of Cape Town and Skirrow's protocols used in isolation of Campylobacter in humans and broilers was carried out in a cross-sectional study in Morogoro, Tanzania. A total of 176 and 158 human stool and broiler intestinal samples were collected, respectively. While human stool samples were collected from selected health centers, broiler intestinal samples were obtained from selected farms and chicken markets. Samples were inoculated and cultured in duplicate using two protocols and prevalence of Campylobacter were established. In humans, the prevalence of Campylobacter isolates was significantly higher (P < 0.001) (21.6%) with Cape Town protocol than Skirrow's method (9.1%). Similarly, a higher prevalence (P < 0.05) in broilers was recorded in Cape Town protocol (77.8%) than Skirrow's method (66.5%). There was a moderate (0.53) Kappa test of agreement between Skirrow's and Cape Town protocols for human samples and substantial agreement (0.72) for broiler samples. This demonstrates that Cape Town protocol is superior over the Skirrow's protocol in Campylobacter isolation. Campylobacter jejuni, Campylobacter coli and Campylobacter lari were the Campylobacter spp. isolated. In humans, C. jejuni accounted for 92.1% and 87.5% of all positive samples with Cape Town and Skirrow's protocols, respectively. In broilers, C. jejuni was isolated at 91.1% and 92.5% of all species obtained with Cape Town and Skirrow's protocols, respectively. This shows that C. jejuni is the common species that may be circulating from either broilers to humans or other animals and vice versa. The present study has introduced Cape Town protocol in Tanzania for Campylobacter isolation from human and animal samples, which is expected to improve the isolation of Campylobacter species. Cape Town protocol may also be a good alternative for use in routine isolation of Campylobacter.

Occurrences of thermophilic Campylobacter in pigs slaughtered at Morogoro slaughter slabs, Tanzania.

Occurrences of thermophlic Campylobacter in pigs and pig carcasses was investigated in a cross-sectional study that was carried out in three selected slaughter slabs in Morogoro municipality, Tanzania. Before sampling, the slab hygiene, slaughter, carcass dressing, and meat handling was assessed. Fecal samples were collected from 66 slaughter pigs at the kill floor. After slaughter, a 100-cm(2) area on medial surface of the thigh muscles of dressed carcasses was sampled using sterile cotton swabs. Thereafter, the jejunal, cecal, and colon contents were also sampled. The samples were subjected to standard bacteriological examination using Skirrows protocol. In all slaughter slabs visited, it was found that pig slaughter, dressing, and meat handling was done on the ground under unhygienic condition. All the slaughter slab environment were dirty and had neither tap water or drainage systems. Thermophilic Campylobacter prevalence in slaughtered pig was 66.7% while contamination rate of dressed carcasses was 10.6%. Of the Campylobacter-positive carcasses, five (12.2%) were from the animals which were also positive to Campylobacter. The isolation rate of Campylobacter in the cecum was higher (34.8%) compared to the small intestines (28.8%) and colon (16.7%) although the difference was not statistically significant (P > 0.05). Campylobacter jejuni was the most prevalent species as it constituted 74% of all isolates, while Campylobacter coli was isolated at 26%. This suggests possible risks of infection to people through consumption of contaminated pork or through contact with infected pigs. Cecum was found to be the major part of intestine highly colonized by Campylobacter.

Antimicrobial Use, Residues, Resistance and Governance in the Food and Agriculture Sectors, Tanzania.

All infections are potentially curable as long as the etiological agents are susceptible to antimicrobials. The increased rate at which antimicrobials are becoming ineffective is a global health risk of increasing concern that threatens withdrawal of beneficial antimicrobials for disease control. The increased demand for food of animal origin, in particular eggs, meat and milk has led to intensification and commercial production systems where excessive use and misuse of antimicrobials may prevail. Antimicrobials, handled and used by farmers and animal attendants with no formal education, may be predisposed to incorrect dosages, misuse, incorrect applications and non-adherence to withdrawal periods. This study was conducted to assess the regulatory roles and governance of antimicrobials, establish the pattern and extent of their use, evaluate the antimicrobial residues and resistance in the food animals and crop agriculture value chains, and relate these findings to existing strategies in place for combating the emergence of antimicrobial resistance in Tanzania. A multimethod approach (desk review, field study and interviews) was used. Relevant establishments were also visited. High levels of resistance to penicillin G, chloramphenicol, streptomycin and oxytetracycline have been reported, especially for Actinobacter pyogenes, Staphylococcus hyicus, Staphylococcus intermedius and Staphylococcus aureus from dairy cattle with mastitis and in humans. Similar trends were found in poultry where eggs and meat are contaminated with Escherichia coli strains resistant to amoxicillin + clavulanate, sulphamethoxazole and neomycin. An increasing trend of emerging multidrug resistant E. coli, Klebsiella pneumoniae, Staphylococcus aureus and Salmonella was also found in food animals. An increase in methicillin resistant Staphlococcus aureus (MRSA) and extended-spectrum beta-lactamase (ESBL) in the livestock sector in Tanzania have been reported. The pathogens isolated in animals were resistant to ampicillin, augmentin, gentamicin, co-trimoxazole, tetracycline, amoxicillin, streptomycin, nalidixic acid, azithromycin, chloramphenicol, tylosin, erythromycin, cefuroxime, norfloxacin and ciprofloxacin. An increased usage of antimicrobials for prophylaxis, and therapeutics against pathogens and for growth promotion in livestock, aquaculture and crop production were observed. A One Health strategic approach is advocated to combat antimicrobial resistance (AMR) in the food and agriculture sectors in Tanzania. Practical recommendations include (a) legislation review and implementation; (b) antimicrobial use (AMU), AMR and antimicrobial residue (AR) awareness and advocacy among stakeholders along the value chain; (c) strengthening of surveillance and monitoring programs for AMU, AMR and AR; (d) enhanced development and use of rapid and innovative diagnostic tests and the promotion of biosecurity principles; and (e) good husbandry practices. The utilization of this information to improve public health policies and reduce the burden of AMR will be beneficial.

Assessment of pollution in sewage ponds using biomarker responses in wild African sharptooth catfish (Clarias gariepinus) in Tanzania.

The interactive effects of mixed pollutants in sewage wastewater on biomarker responses were investigated using wild male African sharptooth catfish (Clarias gariepinus) in Morogoro, Tanzania. A total of 58 fish were used, of which 21 were from Mindu dam (reference site) and 22, 9 and 10 from Mafisa, Mazimbu and Mzumbe sewage ponds, respectively. Liver somatic index (LSI) and gonadosomatic index (GSI) were significantly greater (two- to threefold) and (five- to sixfold), respectively, in fish from all sewage ponds. Haemoglobin concentration and gill filament 7-ethoxyresurufin O-deethylase (EROD) activities were significantly higher (1.2-fold and twofold, respectively) in fish from Mzumbe sewage ponds than in fish from Mindu dam, whereas liver EROD activity was significantly higher in fish from Mzumbe and Mafisa sewage ponds (5-fold). A HPLC method for determination of enzymatically formed p-nitrophenyl-glucuronide (PNPG) was developed and applied to measure UDP-glucuronosyl transferase (UGT) activities that was significantly higher in fish from all sewage ponds (2-2.5-fold) than in fish from Mindu dam. Kinetic characteristics and assay dependence of UGT were studied with microsomal preparations. Metallothionein (MT) content was significantly lower (three- to fourfold) in fish from sewage ponds than in fish from Mindu dam, and corresponded with cumulative levels of cadmium, lead and mercury. Condition factor, vitellogenin (Vtg), acetylcholinesterase (AChE) activities in plasma, eyes and brain, haematocrit, plasma protein and cytosolic glutathione S-transferase (GST) activities were comparable in fish from sewage ponds and Mindu dam. Although specific pollutants other than the metals were not identified by chemical analysis, application of a suite of biomarkers in C. gariepinus demonstrated that all sewage ponds were contaminated by pollutants of public health concern.

Assessment of acetylcholinesterase activity in Clarias gariepinus as a biomarker of organophosphate and carbamate exposure.

The objective of this study was to investigate the response of acetylcholinesterase (AChE) activities in Clarias gariepinus in response to Organophosphates (Ops) and carbamate exposure. The AChE activities were determined in plasma, and eye and brain homogenates of unexposed and exposed fish using Ellman's method and 5,5'-dithiobis-2-nitrobenzoic acid (DTNB) chromophore. The baseline AChE activities in plasma, eyes and brain tissues in unexposed fish were comparable between males and females (P > 0.05). Concentrations of pesticides that inhibited 50% (IC(50)) of AChE activities in brain homogenates following in vitro exposures were 0.003, 0.03, 0.15, 190, 0.2, 0.003 and 0.002 microM for carbaryl, chlorfenvinphos, diazinon, dimethoate, fenitrothion, pirimiphosmethyl and profenofos, respectively. The in vivo dose-effect relationships were assessed using chlorfenvinphos and carbaryl at different concentrations that ranged from 0.0003 to 0.06 microM and 0.0005 to 0.05 microM, respectively. Acetylcholinesterase activities were comparable in plasma, and eye and brain homogenates from control and carbaryl-exposed fish. Following exposure of fish to chlorfenvinphos at concentrations above 0.03 microM, a significant inhibition of AChE activities in plasma (84%) and eye homogenate (50%) was observed. The AChE activities in brain homogenate were comparable between chlorfenvinphos-exposed fish and controls. Because carbaryl cause reversible inhibition of AChE activities was found to be more potent than chlorfenvinphos that cause irreversible inhibition following in vitro exposure. Contrary, carbaryl was less potent than chlorfenvinphos after in vivo exposure possibly due to more rapid biotransformation of carbaryl than chlorfenvinphos. Findings from this study have demonstrated that inhibition of AChE activity in C. gariepinus is a useful biomarker in assessing aquatic environment contaminated by anticholinesterases.

Calf health and management in smallholder dairy farms in Tanzania.

Smallholder farmers' knowledge and practice of dairy calf management on 129 farms with calves less than 10 months of age in Southeastern and Southern Highland areas of Tanzania was assessed. The method of study included both a farm visit and completion of a questionnaire. Most of the farmers were female, with a primary level of education, and majority kept 1-3 milking cows that yielded 6-10 l milk/cow/day. Most of the calves were fed milk using a residual calf suckling system. Weaning age was 3-8 months. Overall, the body condition of the calves was poor, ranged from 1 to 2.5 with a mode of 2. The majority of the farmers believed that helminthosis was the most common disease condition affecting the calves; diarrhea was ranked as the second. Calf death was reported by 20% of the farmers to have occurred in their herd lasting the 2 years prior to the study. Calf body condition score was related to body weight for calves younger than 9 weeks, and older than 23 weeks of age, whereas no such relationship existed in the age group 9 to 23 weeks. The sex distribution was skewed with less male calves being older than 23 weeks. We hypothesize that male calves experience inferior management compared with female calves. This study demonstrates a low level of knowledge on, and poor practices of calf management among the surveyed farmers that suggest the need for educational intervention.

Genome-Based Analysis of Extended-Spectrum ß-Lactamase-Producing Escherichia coli in the Aquatic Environment and Nile Perch (Lates niloticus) of Lake Victoria, Tanzania.

Extended-spectrum ß-lactamase (ESBL)-producing bacteria constitute an emerging global health issue with food products being vehicles of transmission and the aquatic environments serving as potential reservoirs. This study aimed to characterize ESBL-producing Escherichia coli in Nile perch and water from Lake Victoria in Tanzania. A total of 180 samples of Nile perch and 60 water samples were screened for ESBL-producing E. coli on MacConkey agar supplemented with 2 µg/ml of cefotaxime and confirmed by bla CTX-M and bla TEM PCR. Antimicrobial resistance was determined by the disk diffusion method, and the ESBL-producing isolates were whole genome sequencing (WGS). ESBL-producing E. coli were detected in eight of the 180 analyzed Nile perch samples, and only one water sample was positive (1.7%, n = 60). Isolates were resistant to sulfamethoxazole-trimethoprim (100%), ampicillin/cloxacillin (100%), erythromycin 72.7% (8/11), tetracycline 90.9% (10/11), and nalidixic acid 63.6% (7/11). This mostly corroborates the resistance genes that they carried for sulfonamides (sul1 and sul2), trimethoprim (dfrA and dfrB), aminoglycosides [aac(3)-IId, strA, and strB], tetracycline [tet(B) and tet(D)], and fluoroquinolones (qepA4). They harbored plasmid replicon types IncF, IncX, IncQ, and Col and carried bla CTX-M- 15 and bla TEM- 1 B genes generally found on the same contigs as the IncF plasmid replicon. Although epidemiologically unrelated, the strains formed three separate sequence type-phylogroup-serotype-specific clusters: C1, C2, and C3. Cluster C1 included five strains (3 to 13 SNPs) belonging to ST167, phylogroup A, and serotype O9:H21; the two C2 strains (11 SNPs) belong to ST156, phylogroup B1, and serotype ONT:H28; and C3 was made up of four strains (SNPs ranged from 4 to 17) of ST636, phylogroup B2, and serotype O45:H7. The common virulence gene gad was reported in all strains. In addition, strains in C2 and C3 possessed iss, lpfA, and nfaE virulence genes, and the vat gene was found only in C3. The present study reports the occurrence of multidrug-resistant ESBL-producing E. coli carrying plasmid-mediated ESBL genes in offshore water and Nile perch in Lake Victoria. Strains formed three clonal clusters of unknown origin. This study reveals that the Lake may serve as reservoir for ESBL-producing bacteria that can be transmitted by fish as a food chain hazard of One-Health concern.

Vitellogenin in African sharptooth catfish (Clarias gariepinus): purification, characterization, and ELISA development.

Vitellogenin (Vtg) induction in African sharptooth catfish (Clarias gariepinus) was assessed in order to develop a method for monitoring estrogenic pollution in African freshwater systems. Clarias gariepinus Vtg (Cg-Vtg) was purified from serum obtained from 17alpha-ethynylestradiol (EE2)-exposed fish and polyclonal antibodies against Cg-Vtg were raised. An enzyme-linked immunosorbent assay (ELISA) was developed and the induction and kinetics of Vtg were assessed in male fish in three different exposure trials using both natural estrogen (17alpha-estradiol [E2]) and synthetic EE2. Concentrations of EE2 in water and levels of EE2 conjugates in bile were quantified by liquid chromatography-mass spectrometry (LC-MS). In addition, co-administration of E2 and benzo[a]pyrene (BaP) were studied. Vtg was induced in all exposure trials and the maximum induction was observed 1 wk after exposure. Exposure of male C. gariepinus to 1.4, 2.7, and 13.9 microg/ml EE2 induced Vtg synthesis at all concentrations. BaP did not influence the Vtg kinetics. However, an increased rate of biliary excretion of EE2 was observed when BaP was additionally administered. In conclusion, Vtg is induced in male C. gariepinus after exposure to both E2 and EE2, rendering it a suitable biomarker for endocrine-disrupting chemicals in African freshwater systems.

Phenotypic and molecular detection of Aeromonads infection in farmed Nile tilapia in Southern highland and Northern Tanzania.

Aeromonads disease outbreaks are now becoming a common phenomenon in freshwater farmed fish worldwide. In Tanzania, the aquaculture field is increasingly growing save to sustain food protein demand and strengthen household income. To avoid losses that tilapia fish farmers might account, information on magnitude of infection and characteristics of the aetiological agent is vital. This study aimed to establish the prevalence of aeromonads infection in farmed tilapia and assess pond and fish health management practices. A cross sectional study was carried out between February 2017 and October 2018 and a total of 816 whole fish samples were aseptically collected from 32 ponds in Ruvuma, Mbeya, Iringa and Kilimanjaro regions. During sampling, water quality parameters were taken and questionnaires to assess the knowledge of farmers were also provided. Isolation and identification of bacteria was conducted using conventional biotyping and molecular techniques. A total of 201 (80.4%) of 250 isolates that were conventionally identified were confirmed to be aeromonads by amplification of 820 bp rpoD gene, making the overall prevalence of 24.6% (201, n = 816). Sequencing of rpoD gene and phylogenetic analysis revealed two aeromonads species, Aeromonas hydrophila and Aeromonas veronii. To the best of our knowledge this is the first report to establish the prevalence of aeromonads in apparently healthy farmed tilapia in Southern highlands and Northern zone of Tanzania. In addition it was observed that farmers were lacking proper knowledge and awareness on pond management practices and fish health management. In conclusion, the infection rate of aeromonads in apparently health tilapia coupled with lack of proper knowledge and awareness on pond and fish health management by fish farmers in the study area poses risk of diseases outbreaks in their farms in future. Therefore, it is recommended that the farmers should be trained on basic pond and fish health management and control strategies.

Current State of Modern Biotechnological-Based Aeromonas hydrophila Vaccines for Aquaculture: A Systematic Review.

This systematic review describes what "the cutting edge vaccines for Aeromonas hydrophila are". The focus is on types of high tech biotechnological based vaccines, target gene or antigen in developing these vaccines, and challenge model fish species used in vaccines efficacy testing. Vaccines delivery methods, immune response, and their efficacy, adjuvant or carrier systems used, and the overall experimental setup or design of the vaccines under investigation are also described. The search for the original papers published between 2009 and 2018 was conducted in June of 2018, using the PubMed and Google scholar electronic database. Twenty-three (23/4386) studies were included in the final assembly using PRISMA guidelines (Protocol not registered). Recombinant protein vaccines were the highly experimented type of the modern biotechnological based vaccines identified in the selected studies (16/23; 70%). Outer membrane proteins (OMPs) of different ß-barrels were shown to be a potential antigenic entity for A. hydrophila vaccines (57%). Intraperitoneal route with conventional carries or adjuvants was the highly applied delivery system while very few studies used herbal based vaccine adjuvants and nanomaterial as a vaccine carrier. Variation was observed in terms of protection levels in the selected studies. The experimental designs partly contributed to the observed variation. Therefore, recombinant vaccines that use new carrier system technologies and delivered through oral route in feeds would have been of great value for use in the prevention and control of A. hydrophila infections in fish. Despite the usefulness as academic tools to identify what is important in pathogenicity of the etiological agent to the host fish, these vaccines are only economically viable in very high-value animals. Therefore, if vaccination is a good option for A. hydrophila group, then simple autogenous vaccines based on accurate typing and evidence-based definition of the epidemiological unit for their use would be the most viable approach in terms of both efficacy and economic feasibility especially in low and middle-income countries (LMIC).

Tilapia (Oreochromis niloticus) as a Putative Reservoir Host for Survival and Transmission of Vibrio cholerae O1 Biotype El Tor in the Aquatic Environment.

Studies have reported the occurrence of Vibrio cholerae in fish but little is known about the interaction between fish and toxigenic V. cholerae as opposed to phytoplankton, which are well-established aquatic reservoirs for V. cholerae. The present study determined the role of tilapia (Oreochromis niloticus) as a reservoir host for survival and transmission of V. cholerae in aquatic environments. Three experiments were performed with one repetition each, where O. niloticus (∼2 g) kept in beakers were inoculated with four V. cholerae strains (5 × 107 cfu/mL). Firstly, infected tilapia were kept in stagnant water and fed live brine shrimp (Artemia salina) larvae daily. Secondly, infected tilapia were kept without feeding and water was changed every 24 h. Thirdly, infected tilapia were fed and water was renewed daily. Infected tilapia and non-infected controls were sacrificed on days 1, 2, 3, 7, and 14 post-inoculation and V. cholerae were enumerated in intestinal content and water. Another experiment assessed the transmission of V. cholerae from infected to non-infected tilapia. The study revealed that El Tor biotype V. cholerae O1 and V. cholerae non-O1 colonized tilapia intestines and persisted at stable concentrations during the second week of the experiment whereas the Classical biotype was undetectable after 1 week. In stagnant water with feeding, V. cholerae counts dropped to 105 cfu/ml in water and from 107 to 104 cfu/intestine in fish after 14 days. When water was renewed, counts in water decreased from 107 to 103 cfu/ml and intestinal counts went from 106 to 102 cfu/intestine regardless of feeding. All strains were transmitted from infected to naïve fish after 24 h of cohabitation. Tilapia like other fish may play an essential role in the survival and dissemination of V. cholerae O1 in aquatic environments, e.g., the seventh pandemic strains mostly. In this study, tilapia were exposed to high concentrations of V. cholerae to ensure initial uptake and follow-up studies with lower doses resembling natural concentrations of V. cholerae in the aquatic environment are needed to confirm our findings.