Artificial membrane-feeding techniques have replaced direct feeding on animals for the maintenance of malaria and arbovirus vectors in many laboratories. Membrane feeding facilitates controlled experimentation of pathogen transmission during mosquito feeding. Sheep blood is commonly used due to its availability and low cost. We evaluated the impact of blood source (human, guinea pig, sheep, and hamster via direct feeding) on feeding rates, adult survival, fecundity, hatching rates, and developmental times for five species of laboratory-colonized mosquitoes (Anopheles dirus, An. cracens, An. minimus, An. sawadwongporni, and Ae. aegypti). We found that feeding rates differ among blood sources within mosquito species. Survival, fecundity, and hatching rates were lower in all Anopheles species and Ae. aegypti after membrane feeding on sheep blood. Survival rates seven days post-feeding on sheep blood were significantly lower (P<0.05) for An. dirus (84.2%), An. minimus (67.2%), An. sawadwongporni (51.5%), and An. cracens (35.5%) relative to other blood sources. An. minimus and An. sawadwongporni laid no eggs by seven days post-feeding with sheep blood, while An. dirus and An. cracens produced significantly fewer numbers of eggs and demonstrated significantly lower hatching rates relative to what was observed with the other blood sources. These findings support the conclusion that sheep blood is not a suitable blood source for laboratory rearing of Anopheles spp. Journal of Vector Ecology 38 (1): 38-45. 2013.

The ticks, Hyalomma (Euhyalomma) dromedarii Koch, 1844 and Hyalomma (Euhyalomma) schulzei Olenev, 1931, are considered to be the species most closely associated with camels. H. dromedarii can behave as a three-, two-, or one-host species, with the two-host life cycle seemingly most common. Camels are the main hosts of the adults, which also parasitize other domestic animals. Nymphs and larvae can use the same hosts, especially camels, as the adults, but can also parasitize rodents, leporids, hedgehogs, and birds. H. dromedarii is widely distributed in North Africa, the northern regions of West, Central, and East Africa, Arabia, Asia Minor, the Middle East, and Central and South Asia. H. schulzei is a two-host species. Camels are the principal hosts of the adults, with some records from cattle and goats, whereas the immature stages infest hares, burrowing rodents, and hedgehogs. H. schulzei has a more limited geographic distribution in Asia and Egypt than H. dromedarii, and with the exception of southeastern Iran, it is a fairly uncommon tick. Among other features that are fairly similar, males of H. dromedarii can be distinguished from those of H. schulzei by a narrow, subtriangular parma, usually very large subanal shields, and a long dorsal prolongation of the spiracular plates. Males of H. schulzei have a broad and rectangular parma, paramedian festoons that protrude posteriorly, smaller subanal shields, and a very short dorsal prolongation of the spiracular plates. The females of H. dromedarii can be distinguished from those of H. schulzei by a narrow V-shaped genital aperture compared with a very wide, deep, U-shaped genital aperture. Here all the parasitic stages of both species are illustrated and redescribed, and characteristics that distinguish the adults from those of other closely related species are supplied. Data on their hosts, geographic distribution and disease relationships are also provided.

Abstract. Plasmodium vivax accounts for an increasing fraction of malaria infections in Thailand and Cambodia. We compared P. vivax genetic complexity and antimalarial resistance patterns in the two countries. Use of a heteroduplex tracking assay targeting the merozoite surface protein 1 gene revealed that vivax infections in both countries are frequently polyclonal (84%), with parasites that are highly diverse (H E = 0.86) but closely related (G ST = 0.18). Following a history of different drug policies in Thailand and Cambodia, distinct patterns of antimalarial resistance have emerged: most Cambodian isolates harbor the P. vivax multidrug resistance gene 1 ( pvmdr1) 976F mutation associated with chloroquine resistance (89% versus 8%, P 0.001), whereas Thai isolates more often display increased pvmdr1 copy number (39% versus 4%, P 0.001). Finally, genotyping of paired isolates from individuals suspected of suffering relapse supports a complex scheme of relapse whereby recurrence of multiple identical variants is sometimes accompanied by the appearance of novel variants.

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Rodents are the natural hosts for Leptotrombidium mites that transmit Orientia tsutsugamushi, the causative agent of scrub typhus, a potentially fatal febrile human disease. Utilizing mite lines that included O. tsutsugamushi infected and non-infected Leptotrombidium species we investigated the varied infection response of outbred mice (ICR) exposed to L. chiangraiensis (Lc), L. imphalum (Li) and L. deliense (Ld). Each of six mite lines (Lc1, Lc5, Li3, Li4, Li7 and Ld) was separately placed in the inner ears of ICR mice either as a single individual (individual feeding, IF) or as a group of 2-4 individuals (pool feeding, PF). The species of infected chigger feeding on mice significantly affected mortality rates of the mice, with mite lines of Lc causing higher mean (±SE) mortality (90.7 ± 3.6 %) than mite lines of Li (62.9 ± 5.6 %) or Ld (53.6 ± 5.8 %). Mouse responses which included time to death, food consumption and total mice weight change depended on mite species and their O. tsutsugamushi genotype, more than on feeding procedure (IF vs. PF) except for mite lines within the Lc. Infected mite lines of Lc were the most virulent infected mites assessed whereas the infected Ld species was the least virulent for the ICR. Mice killed by various mite lines showed enlarged spleens and produced ascites. The results of this investigation of the clinical responses of ICR mice to feeding by various infected mite lines indicated that the different species of infected mites and their O. tsutsugamushi genotype produced different clinical presentations in ICR mice, a scrub typhus mouse model which mimics the natural transmission of O. tsutsugamushi that is critical for understanding scrub typhus disease in terms of natural transmission, host-pathogen-vector interaction and vaccine development.