Evaluation of effectiveness and safety of Subolesin anti-tick vaccine in Ugandan multi-site field trial.

Vaccines are the most effective and sustainable intervention to control ticks and tick-borne diseases (TBD). Using a personalized vaccine design based on regional tick genotypes, a Rhipicephalus appendiculatus Subolesin protective antigen was used in a field trial evaluating tick vaccine efficacy, effectiveness, and safety in cattle infested with multiple tick species in different Ugandan agro-ecological zones. Vaccination with SUB was safe with a protective capacity against anemia and infection, and reduced the number of infested cattle, tick fitness (feeding and reproduction) with vaccine effectiveness against multiple tick species between 93.2% at 167-196 days post-vaccination (dpv) and 61.4% at 251-327 dpv. Total integrated vaccine efficacy/effectiveness was estimated as 98.8%. The Subolesin-based vaccine is protective against multiple cattle tick infestations under field conditions in Uganda. These results support registration and commercialization of the vaccine to reduce tick populations and associated risks for human and animal TBD and chemical acaracides in Uganda.

A unified Foot and Mouth Disease dataset for Uganda: evaluating machine learning predictive performance degradation under varying distributions.

In Uganda, the absence of a unified dataset for constructing machine learning models to predict Foot and Mouth Disease outbreaks hinders preparedness. Although machine learning models exhibit excellent predictive performance for Foot and Mouth Disease outbreaks under stationary conditions, they are susceptible to performance degradation in non-stationary environments. Rainfall and temperature are key factors influencing these outbreaks, and their variability due to climate change can significantly impact predictive performance. This study created a unified Foot and Mouth Disease dataset by integrating disparate sources and pre-processing data using mean imputation, duplicate removal, visualization, and merging techniques. To evaluate performance degradation, seven machine learning models were trained and assessed using metrics including accuracy, area under the receiver operating characteristic curve, recall, precision and F1-score. The dataset showed a significant class imbalance with more non-outbreaks than outbreaks, requiring data augmentation methods. Variability in rainfall and temperature impacted predictive performance, causing notable degradation. Random Forest with borderline SMOTE was the top-performing model in a stationary environment, achieving 92% accuracy, 0.97 area under the receiver operating characteristic curve, 0.94 recall, 0.90 precision, and 0.92 F1-score. However, under varying distributions, all models exhibited significant performance degradation, with random forest accuracy dropping to 46%, area under the receiver operating characteristic curve to 0.58, recall to 0.03, precision to 0.24, and F1-score to 0.06. This study underscores the creation of a unified Foot and Mouth Disease dataset for Uganda and reveals significant performance degradation in seven machine learning models under varying distributions. These findings highlight the need for new methods to address the impact of distribution variability on predictive performance.

Bibliometric analysis for the identification of main limitations and future directions of vaccines for the control of ticks and tick-borne pathogens in Uganda.

Ticks and tick-borne diseases (TBD) are a growing threat for human and animal health worldwide with high incidence in African countries such as Uganda where it affects cattle health and production. Considering recent advances in bibliometric analysis, in this review we used a bibliometric descriptive approach for the analysis of publications and patents in the fields of ticks, TBD, and vaccines in Uganda. The results showed that major gaps and limitations are associated with (i) low contributions from Ugandan institutions, (ii) limited international collaborations, (iii) poor impact of translational research, and (iv) little research on tick control vaccines. The results were then used to propose future directions to approach these limitations in Uganda. Although ongoing initiatives and international collaborations are contributing to address major gaps and limitations, future directions should advance in these collaborative projects together with new initiatives addressing (i) basic and translational research on TBD such as CCHF and ASF, (ii) participation of Ugandan institutions in new international consortia in this area, (iii) promoting communication of these initiatives to Ugandan cattle holders and general population to attract support from public and private sectors, (iv) stimulate and support scientific publications and patents with participation of Ugandan scientists, and (v) build and implement production capacity for vaccines in Uganda. These results contribute to guiding Ugandan scientists and national authorities to face challenges posed by ticks and TBD with implications for other African countries.

Cloning of gonadotropin Gph-alpha, FSH-beta and LH-beta subunits and seasonal profiles of steroid hormones in wild-caught Nile perch, Lates niloticus.

The Nile perch (np; Lates niloticus) is a freshwater teleost species with a potential for aquaculture in freshwater surroundings. However, wild-caught breeders have persistently failed to spawn spontaneously in captivity. Cloning of the gonadotropin subunits and analysing seasonal variation in reproductive hormone levels for a 1-year period were done to gain knowledge on the physiological basis underlying the reproductive biology of np. The ß-follicle-stimulating hormone (FSH-ß) and ß-luteinizing hormone (LH-ß) subunits and their common α-glycoprotein (Gph-α) subunit were cloned using 3' and 5' RACE-PCR. The nucleotide sequences of the npgph-α, npfsh-ß, and nplh-ß subunits were 664, 580 and 675 nucleotides in length, encoding peptides of 124, 120 and 148 amino acids, respectively. The deduced amino acid sequence of each mature subunit showed high similarity with its counterparts in other teleost. Sequence analysis showed that npFSH-ß is more similar to higher vertebrate FSH-ßs than to higher vertebrate LH-ßs. Heterologous immunoassay was calibrated to analyse pituitary LH levels. While the LH immunoassay showed parallelism of npLH with that of tilapia (ta), no parallelism for FSH was found. Levels of pituitary LH were higher in females at gonadal stages of vitellogenic oocytes, mature secondary oocytes and mature tertiary oocytes with migrating nucleus than in pre-vitellogenic oocytes and early and late perinucleolus oocytes. Using competitive steroid ELISA, variations in the levels of the steroid hormones 11-ketotestosterone (11-KT) in males and E2 in females were characterized in relation to month and reproductive index of Nile perch. Our findings show that in females, gonadosomatic index and plasma E2 were highly correlated (R2 = 0.699, n = 172) and peaked from September to November while in males, the gonadosomatic index and plasma 11-KT peaked from October to November. In female fish, both steroid hormones were detected in the plasma but greatly varied in concentrations. E2 in particular, increased with the developmental stage of the gonads. The levels of steroid hormones, E2 and 11-KT in females and males respectively increased with fish size (total lengths) and suggest that females mature at a body length of 40-59 cm than their counter part males that mature at a total length of 60-70 cm. Taken together, we describe seasonal endocrine differences in wild-caught adult Nile perch which could potentially be exploited to manipulate the reproductive axis in cultured breeders.

Scanning electron microscopy of the gastrointestinal tract of nile perch (lates niloticus, linneaus, 1758) / Microscopía electrónica de barrido del tracto gastrointestinal de la perca del nilo (lates niloticus, linnaeus, 1758)

The morphology of the gastrointestinal tract of adult Nile perch was described using standard SEM procedures. Investigations revealed the presence of cardiform teeth in the oral cavity, goblet cells and finger print-like microridges on the hard palate and oesophagus lumenal surface. Elaborate patterns and bacterial cells were observed on the stomach lumenal surface and intense foldings in the intestinal region. These observations provide a better understanding of the morphology of the gut in Nile perch and how it is suited for its digestive function.

El objetivo fue describir la morfología del tracto gastrointestinal de la perca del Nilo adulta mediante microscopía electrónica de barrido estándar. La investigación reveló la presencia de dientes cardiformes en la cavidad oral, células caliciformes y microcrestas como huellas digitales en el paladar duro y la superficie luminal del esófago. Se observaron patrones elaborados, así como bacterias en la superficie luminal del estómago, y plegamientos marcados en la región intestinal. Estas observaciones proporcionan una mejor comprensión de la morfología del intestino de la perca del Nilo y como se adapta para su función digestiva.