Using Combined Morphological, Allometric and Molecular Approaches to Identify Species of the Genus Raillietiella (Pentastomida)

Taxonomic studies of parasites can be severely compromised if the host species affects parasite morphology; an uncritical analysis might recognize multiple taxa simply because of phenotypically plastic responses of parasite morphology to host physiology. Pentastomids of the genus Raillietiella are endoparasitic crustaceans primarily infecting the respiratory system of carnivorous reptiles, but also recorded from bufonid anurans. The delineation of pentastomids at the generic level is clear, but the taxonomic status of many species is not. We collected raillietiellids from lungs of the invasive cane toad (Rhinella marina), the invasive Asian house gecko (Hemidactylus frenatus), and a native tree frog (Litoria caerulea) in tropical Australia, and employed a combination of genetic analyses, and traditional and novel morphological methods to clarify their identity. Conventional analyses of parasite morphology (which focus on raw values of morphological traits) revealed two discrete clusters in terms of pentastome hook size, implying two different species of pentastomes: one from toads and a tree frog (Raillietiella indica) and another from lizards (Raillietiella frenatus). However, these clusters disappeared in allometric analyses that took pentastome body size into account, suggesting that only a single pentastome taxon may be involved. Our molecular data revealed no genetic differences between parasites in toads versus lizards, confirming that there was only one species: R. frenatus. This pentastome (previously known only from lizards) clearly is also capable of maturing in anurans. Our analyses show that the morphological features used in pentastomid taxonomy change as the parasite transitions through developmental stages in the definitive host. To facilitate valid descriptions of new species of pentastomes, future taxonomic work should include both morphological measurements (incorporating quantitative measures of body size and hook bluntness) and molecular data

Evaluation of Questionnaire, Reagent Strip and Egg Count as Diagnostic Techniques for Confirming Urinary Schistosomiasis in School Children, Edo State, Nigeria

A longitudinal study covering 55 months evaluated the three diagnostic tools used for confirmation of prevalence of urinary schistosomiasis among 1151 consented primary school pupils in 13 communities of Edo State, Nigeria. Questionnaire, reagent strip method and parasitological  examination were employed. Urine samples collected were processed using centrifugation and concentration method and deposits examined microscopically for eggs of Schistosoma haematobium. The mean  prevalence from the three diagnostic methods was 32%, as prevalence by questionnaire method was 19%, reagent strip (56%) and microscopy (21%). Age related prevalence of infection for the three methods was observed to increase with increasing age of the pupils. Sex related prevalence of infection was observed to be slightly higher in males (25%) than in females (17%) but not statistically significant (p>0.01). There was a significant relationship between questionnaire study and S. haematobium infection. Self-diagnosis with the aid of gross haematuria was a reliable diagnostic tool for S. haematobium infection, because, the difference between it and the gold standard method was insignificant. In conclusion, therefore, the reagent strip haematuria was shown to be a good indicator of S. haematobium infection that could be used repeatedly but a  combination of the three indicators had been established as a better predictor of S. haematobium infection. The sensitivity and specificity of ‘passing out blood in urine’ reading alone may be sufficient for field conditions in extremely resource –poor settings where no urine reagent strips are available. This may be used as an indicator for infection to detectthe most severely infected individuals by the Primary Health Care workers.Keywords: Diagnostic Techniques, Urinary Schistosomiasis, School Children, Edo State, Nigeria