Visual Analytics of Tuberculosis Detection Rat Performance

The diagnosis of tuberculosis (TB) disease remains a global challenge, and the need for innovative diagnostic approaches is inevitable. Trained African giant pouched rats are the scent TB detection technology for operational research. The adoption of this technology is beneficial to countries with a high TB burden due to its cost-effectiveness and speed than microscopy. However, rats with some factors perform better. Thus, more insights on factors that may affect performance is important to increase rats’ TB detection performance. This paper intends to provide understanding on the factors that influence rats TB detection performance using visual analytics approach. Visual analytics provide insight of data through the combination of computational predictive models and interactive visualizations. Three algorithms such as Decision tree, Random Forest and Naive Bayes were used to predict the factors that influence rats TB detection performance. Hence, our study found that age is the most significant factor, and rats of ages between 3.1 to 6 years portrayed potentiality. The algorithms were validated using the same test data to check their prediction accuracy. The accuracy check showed that the random forest outperforms with an accuracy of 78.82% than the two. However, their accuracies difference is small. The study findings may help rats TB trainers, researchers in rats TB and Information system, and decision makers to improve detection performance. This study recommends further research that incorporates gender factors and a large sample size.

Rats sniff out pulmonary tuberculosis from sputum: a diagnostic accuracy meta-analysis

In Sub-Saharan Africa, African giant pouched rats (Cricetomys gambianus) are trained to identify TB patients by smelling sputum. We conducted a systematic review and meta-analysis of the data to see if this novel method is comparable to traditional laboratory screening and detection methods like Ziehl–Neelsen stain-based assays (ZN) and bacterial culture. The search and data processing strategy is registered at PROSPERO (CRD42019123629). Medline via PubMed, EMBASE, Web of Science, and Cochrane Library databases were systematically searched for the keywords “pouched rat” and “tuberculosis”. Data from 53,181 samples obtained from 24,600 patients were extracted from seven studies. Using sample-wise detection, the sensitivity of the studies was 86.7% [95% CI 80.4–91.2%], while the specificity was 88.4% [95% CI 79.7–93.7%]. For patient-wise detection, the sensitivity was 81.3% [95% CI 64.0–91.4%], while the specificity was 73.4% [95% CI 62.8–81.9%]. Good and excellent classification was assessed by hierarchical summary receiver-operating characteristic analysis for patient-wise and sample-wise detections, respectively. Our study is the first systematic review and meta-analysis of the above relatively inexpensive and rapid screening method. The results indicate that African giant pouched rats can discriminate healthy controls from TB individuals by sniffing sputum with even a higher accuracy than a single ZN screening.

Hematologic and Biochemical Reference Intervals and Urinary Test Results for Wild-caught Adult Southern Giant Pouched Rats (Cricetomys ansorgei)

Southern giant pouched rats (Cricetomys ansorgei) are muroid rodents native to subSaharan Africa. They are increasinglyused as service animals because of their keen sense of smell and are primarily known for clearing minefields in Africa. Theobjectives of this study were to determine hematologic and biochemical reference intervals from clinically healthy wild-caught captive adult rats, to describe the cytochemical staining reactions of peripheral blood leukocytes, and to document urinalysis findings. Blood samples were collected from the coccygeal artery of 60 isoflurane-anesthetized rats (36 males and 24 females) and analyzed with automated hematologic and biochemical analyzers; manual differential cell counts were performed on modified Wright–stained blood smears. Urine was collected by cystocentesis, and dipsticks were analyzed on a urine analyzer, with visual examination of unstained sediments. Samples from a male rat with chronic renal disease were excluded from analysis. Reference intervals were determined according to guidelines established by the American Society of Veterinary Clinical Pathology. Lymphocytes were the dominant leukocyte in peripheral blood and granular lymphocytes were identified in most animals. Male rats had significantly higher RBC, absolute reticulocyte counts, and MCV than did female rats. Minor sex-associated differences in urea nitrogen concentration and GGT activity were noted. Leukocytes showed unique cytochemical staining characteristics. Small amounts of protein and bilirubin were found in the urine of rats of both sexes and of female rats, respectively, particularly in concentrated urine. These results will provide benchmarks for determining health status and identifying disease in this species of rat.

The giant pouched rat (Cricetomys ansorgei) olfactory receptor repertoire

For rodents, olfaction is essential for locating food, recognizing mates and competitors, avoiding predators, and navigating their environment. It is thought that rodents may have expanded olfactory receptor repertoires in order to specialize in olfactory behavior. Despite being the largest clade of mammals and depending on olfaction relatively little work has documented olfactory repertoires outside of the conventional laboratory mice and rats. Here we report the olfactory receptor repertoire of the African giant pouched rat (Cricetomys ansorgei), a Muroid rodent distantly related to mice and rats. The African giant pouched rat is notable for its large cortex and olfactory bulbs relative to its body size compared to other sympatric rodents, which suggests anatomical elaboration of olfactory capabilities. We hypothesized that in addition to anatomical elaboration for olfaction, these pouched rats might also have an expanded olfactory receptor repertoire to enable their olfactory behavior. We examined the composition of the olfactory receptor repertoire to better understand how their sensory capabilities have evolved. We identified 1145 functional olfactory genes, and 260 additional pseudogenes within 301 subfamilies from the African giant pouched rat genome. This repertoire is similar to mice and rats in terms of size, pseudogene percentage and number of subfamilies. Analyses of olfactory receptor gene trees revealed that the pouched rat has 6 expansions in different subfamilies compared to mice, rats and squirrels. We identified 99 orthologous genes conserved among 4 rodent species and an additional 167 conserved genes within the Muroid rodents. The orthologous genes shared within Muroidea suggests that there may be a conserved Muroid-specific olfactory receptor repertoire. We also note that the description of this repertoire can serve as a complement to other studies of rodent olfaction, as the pouched rat is an outgroup within Muroidea. Thus, our data suggest that African giant pouched rats are capable of both natural and trained olfactory behaviors with a typical Muriod olfactory receptor repertoire.