The Transmission of Animal African Trypanosomiasis in Two Districts in the Forest Zone of Ghana.

Animal African trypanosomiasis, also known as nagana, is caused by Trypanosoma species, which cause significant clinical diseases and lead to losses in animal production. We carried out a cross-sectional survey to investigate the composition of vectors and parasite diversity in two districts in the eastern region of Ghana where pigs and cattle were exposed to tsetse bites. We performed cytochrome c oxidase subunit 1 polymerase chain reaction (PCR) to identify tsetse species and internal transcribed spacer 1 PCR to identify Trypanosoma species. Also, we investigated the source of tsetse blood meal based on mitochondrial cytochrome b gene sequence analysis. A total of 229 tsetse, 65 pigs, and 20 cattle were investigated for trypanosomes. An overall vector density of 4.3 tsetse/trap/day was observed. A trypanosome prevalence of 58.9% (95% CI = 52.5-65.1%), 46.2% (95% CI = 34.6-58.1%), and 0.0% (95% CI = 0.0-16.1%) in tsetse, pigs, and cattle, respectively, was detected. Trypanosoma congolense was predominant, with a prevalence of 33.3% (95% CI = 73.3-86.5%) in tsetse. There was evidence of multiple infections in tsetse and pigs. Approximately 39% of the tsetse were positive for multiple infections of T. congolense and Trypanosoma simiae. Parasite prevalence in pigs across the communities was high, with significant differences associated between locations (χ2 = 28.06, 95% CI = 0.05-0.81, P = 0.0009). Tsetse blood meal analysis revealed feeding on domestic Sus scrofa domesticus (pigs) and Phacochoerus africanus (warthogs). Infective tsetse may transmit trypanosomes to livestock and humans in the communities studied.

A digital microscope for the diagnosis of Plasmodium falciparum and Plasmodium vivax, including P. falciparum with hrp2/hrp3 deletion.

Sensitive and accurate malaria diagnosis is required for case management to accelerate control efforts. Diagnosis is particularly challenging where multiple Plasmodium species are endemic, and where P. falciparum hrp2/3 deletions are frequent. The Noul miLab is a fully automated portable digital microscope that prepares a blood film from a droplet of blood, followed by staining and detection of parasites by an algorithm. Infected red blood cells are displayed on the screen of the instrument. Time-to-result is approximately 20 minutes, with less than two minutes hands-on time. We evaluated the miLab among 659 suspected malaria patients in Gondar, Ethiopia, where P. falciparum and P. vivax are endemic, and the frequency of hrp2/3 deletions is high, and 991 patients in Ghana, where P. falciparum transmission is intense. Across both countries combined, the sensitivity of the miLab for P. falciparum was 94.3% at densities >200 parasites/µL by qPCR, and 83% at densities >20 parasites/µL. The miLab was more sensitive than local microscopy, and comparable to RDT. In Ethiopia, the miLab diagnosed 51/52 (98.1%) of P. falciparum infections with hrp2 deletion at densities >20 parasites/µL. Specificity of the miLab was 94.0%. For P. vivax diagnosis in Ethiopia, the sensitivity of the miLab was 97.0% at densities >200 parasites/µL (RDT: 76.8%, microscopy: 67.0%), 93.9% at densities >20 parasites/µL, and specificity was 97.6%. In Ethiopia, where P. falciparum and P. vivax were frequent, the miLab assigned the wrong species to 15/195 mono-infections at densities >20 parasites/µL by qPCR, and identified only 5/18 mixed-species infections correctly. In conclusion, the miLab was more sensitive than microscopy and thus is a valuable addition to the toolkit for malaria diagnosis, particularly for areas with high frequencies of hrp2/3 deletions.

Welcome to the next generation of Malaria Rapid Diagnostic Tests: Comparative Analysis of NxTek Eliminate Malaria P.f, Biocredit Malaria Ag Pf, and SD Bioline Malaria Ag Pf for Plasmodium falciparum Diagnosis in Ghana.

Background: Accurate diagnosis and timely treatment are crucial in combating malaria. Methods: We evaluated the diagnostic performance of three Rapid Diagnostic Tests (RDTs) in diagnosing febrile patients, namely: Abbott NxTek Eliminate Malaria Ag Pf (detecting HRP2), Rapigen Biocredit Malaria Ag Pf (detecting HRP2 and LDH on separate bands), and SD Bioline Malaria Ag Pf (detecting HRP2). Results were compared to qPCR. Results: Among 449 clinical patients, 45.7% (205/449) tested positive by qPCR for P. falciparum with a mean parasite density of 12.5parasites/µL. The sensitivity of the Biocredit RDT was 52.2% (107/205), NxTek RDT was 49.3% (101/205), and Bioline RDT was 40.5% (83/205). When samples with parasite densities lower than 20 parasites/uL were excluded (n=116), a sensitivity of 88.8% (79/89, NxTek), 89.9% (80/89, Biocredit), and 78.7% (70/89, Bioline) was obtained. All three RDTs demonstrated specificity above 95%. The limits of detection was 84 parasites/µL (NxTek), 56 parasites/µL (Biocredit, considering either HRP2 or LDH), and 331 parasites/µL (Bioline). None of the three qPCR-confirmed P. falciparum positive samples, identified solely through the LDH target, carried hrp2/3 deletions. Conclusion: The Biocredit and NxTek RDTs demonstrated comparable diagnostic efficacies and both RDTs performed better than Bioline RDT.

Accuracy of diagnosis among clinical malaria patients: comparing microscopy, RDT and a highly sensitive quantitative PCR looking at the implications for submicroscopic infections.

BACKGROUND: The World Health Organization recommends parasitological confirmation of all suspected malaria cases by microscopy or rapid diagnostic tests (RDTs) before treatment. These conventional tools are widely used for point-of-care diagnosis in spite of their poor sensitivity at low parasite density. Previous studies in Ghana have compared microscopy and RDT using standard 18S rRNA PCR as reference with varying outcomes. However, how these conventional tools compare with ultrasensitive varATS qPCR has not been studied. This study, therefore, sought to investigate the clinical performance of microscopy and RDT assuming highly sensitive varATS qPCR as gold standard. METHODS: 1040 suspected malaria patients were recruited from two primary health care centers in the Ashanti Region of Ghana and tested for malaria by microscopy, RDT, and varATS qPCR. The sensitivity, specificity, and predictive values were assessed using varATS qPCR as gold standard. RESULTS: Parasite prevalence was 17.5%, 24.5%, and 42.1% by microscopy, RDT, and varATS qPCR respectively. Using varATS qPCR as the standard, RDT was more sensitive (55.7% vs 39.3%), equally specific (98.2% vs 98.3%), and reported higher positive (95.7% vs 94.5%) and negative predictive values (75.3% vs 69.0%) than microscopy. Consequently, RDT recorded better diagnostic agreement (kappa = 0.571) with varATS qPCR than microscopy (kappa = 0.409) for clinical detection of malaria. CONCLUSIONS: RDT outperformed microscopy for the diagnosis of Plasmodium falciparum malaria in the study. However, both tests missed over 40% of infections that were detected by varATS qPCR. Novel tools are needed to ensure prompt diagnosis of all clinical malaria cases.