Evaluation of the Clinical Proficiency of RDTs, Microscopy and Nested PCR in the Diagnosis of Symptomatic Malaria in Ilorin, North-Central, Nigeria

BACKGROUND: Accurate laboratory diagnosis of suspected malaria is the hallmark to the control of the disease.AIM: The clinical proficiency of commercial Rapid Diagnostic test kits (RDTs) using nested PCR as quality control was evaluated among patients attending two public healthcare providing institutions in Ilorin, Kwara state, North-Central, Nigeria.METHOD: A cross-sectional evaluation of finger prick blood samples of volunteer patients were accessed for malaria parasites with pLDH, HRP2, Pf, Pf/PAN and nested PCR molecular assays. The data derived were analysed using standard formulae for diagnostic accuracy, and the obtained predictive values were subjected to a comparison with one-way analysis of variance (ANOVA).RESULT: Three hundred and sixty-eight (368) patients comprising 203 (55%) females and 165 (45%) males participated in this study. Routine microscopy revealed that 54 (32.7%) males and 80 (39.4%) was infected with Plasmodium falciparum. SD Bioline (pLDH) 47.4%; Carestart Malaria (HRP2) 49.8% recorded low sensitivities. Micropoint (pfPAN) 82.8% and Micropoint (Mal. Pf) 64.4% recorded a high sensitivity. SD Bioline (pLDH) 67.4%; Carestart Malaria (HRP2) 85.9%; Micropoint (PfPAN) 62.2% and Micropoint (Mal. Pf) 86.7% had high specificities. The positive predictive value (PPV) ranged from 67.7% to 85.94%, while the negative predictive values (NPV) of 64.4% for SD Bioline (pLDH); 86.7% for Carestart Malaria (HRP2); 89.3% for Micropoint (pfPAN) and 58.5% for Micropoint (Mal. Pf). Agarose gel analysis of P. falciparum ssrRNA gene (206 bp) for 28 specimens containing 10% concordant and discordant samples showed that all 12 negative specimens for RDTs and routine microscopy were truly negative for nPCR. However, the remaining 16 specimens were positive for nPCR and showed discrepancies with routine microscopy and RDTs. Cohen’s interrater diagnostic measure analysis revealed that the weighted kappa for the RDTs was moderate 0.417 (p=0.027), 95%CI (0.756, 0.078) and good for nPCR 0.720 (p < 0.001), 95%CI (0.963, 0.477). The area under the curve (AUC) specify that nPCR has been more effective than the RDTs (nPCRAUC = 0.875; p < 0.001 and RDTsAUC = 0.708; p = 0.063).CONCLUSION: A thorough large-scale quality control is advocated on all commercial RDTs being used in most sub-Saharan African countries. This is to avoid double jeopardy consequent upon misdiagnosis on unidentified positive cases serving as pool reservoir for the insect vector and cyclical infection and re-infection of the populace

Seasonal distribution and common management practices of ectoparasites of domestic dogs in Ilorin, Nigeria

In spite of their zoonotic potentials, ectoparasites of domestic animals are less studied in many part of Nigeria. This study therefore investigated the seasonal distribution and common management practices of dogs’ ectoparasites in Ilorin, North-Central Nigeria. Information on dog’s bio-data, activities and control measures adopted by owners were obtained using structured questionnaire. Dogs were examined for ectoparasites using standard parasitological method. Out of the 164(48.9 %) male and 170(51.1 %) female dogs examined, a total of 52.0 % harbored at least one of five species of ectoparasites identified in the study: ticks (Rhipicephalus sanguineus, 70.3 %, Haemaphysalis leachii, 29.4 % and Amblyomma variegatum, 4.5 %), Flea (Ctenocephalides canis, 63.7 %) and lice (Heterodoxus spiniger, 30.0 %). Infestation was higher in males (60.7 %) than females (43.5 %). Multiple infestation particularly combination of tick and flea (34.7 %) were more frequent. Puppies of ≤ 6 months and dogs with short hair (86.5 %) were significantly infested (p<0.05). Analysis of seasonal distribution showed that ectoparasites were more abundant during the rainy season than the dry. The practice of allowing dogs to associate with other dogs; defecate and roam around the premises was significantly associated with increased infestation (p<0.05). Bathing of dogs with locally formulated chemicals significantly reduced infestation; however, they were not recommended acaricides. Some dog owners still employ handpicking, removal by brush or application of kerosene as best practices for controlling ectoparasites; hence, adequate knowledge on safe and reliable methods of control is exigent.Keywords: Dog, Infestation, Ectoparasites, Seasonal distribution, Managemen