Browsing by Author "Davis, Stephen"

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    Comparative and functional morphology of the middle ear in Zambezian mole-rats (Coetomys – Cryptomys, Bathyergidae)
    (Belg. J. Zool, 2005-12) Leirs, Herwig; Makundi, Rhodes H.; Davis, Stephen; Lange, Simone; Burda, Hynek; Assogbadjo, A.E.; Codjia, J.T.C.; Sinsin, B.; Ekue, M.R.M.; Mensah, G.A.; Mgode, G.F.; Mhamphi, G.A.; Katakweba, A. W.; Paemelaere, E; Willekens, N.; Leirs, H.; Machang’u, R.S.; Hartskeerl, R.A.
    Within the family Bathyergidae, the genus Coetomys (Cryptomys) is the most speciose. However, an unambiguous morphological or morphometrical species diagnosis has not been feasible to date. The middle ear structures involved in sound transmission were examined and measured in six species of Zambezian mole-rats of varying body sizes : Coetomys amatus, C. anselli, C. darlingi, C. kafuensis, C. mechowi and C. whytei. Compari- sons revealed many differences in the shape of the middle ear ossicles allowing species differentiation. Bullar vol- ume, eardrum area and cross-sectional area of the bony meatus were positively correlated with body size (as repre- sented by condylo-basal length) whereas the size of middle ear ossicles was rather independent of body size. Middle ears shared typical features with those found in low-frequency hearing mammals. Contrary to the findings in heter- omyids and the Spalax ehrenbergi species complex, within the genus Coetomys, those species occupying more mesic habitats had more efficient tympano-ossicular systems (suggesting more sensitive hearing) than species from drier habitats.
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    Plague and the human flea, Tanzania
    (Emerging Infectious Diseases, 2007) Laudson, Anne; Leirs, Herwig; Makundi, Rhodes H.; Dongen, Stefan Van; Davis, Stephen; Neerinckx, Simon; Deckers, Jozef; Libois, Roland
    Domestic fl eas were collected in 12 villages in the western Usambara Mountains in Tanzania. Of these, 7 are considered villages with high plague frequency, where hu- man plague was recorded during at least 6 of the 17 plague seasons between 1986 and 2004. In the remaining 5 vil- lages with low plague frequency, plague was either rare or unrecorded. Pulex irritans, known as the human fl ea, was the predominant fl ea species (72.4%) in houses. The den- sity of P. irritans, but not of other domestic fl eas, was signifi - cantly higher in villages with a higher plague frequency or incidence. Moreover, the P. irritans index was strongly posi- tively correlated with plague frequency and with the logarith- mically transformed plague incidence. These observations suggest that in Lushoto District human fl eas may play a role in plague epidemiology. These fi ndings are of immediate public health relevance because they provide an indicator that can be surveyed to assess the risk for plague.