Arbovirus of marine mammals: a new alphavirus isolated from the elephant seal louse, Lepidophthirus macrorhini

A novel alphavirus was isolated from the louse Lepidophthirus macrorhini, collected from southern elephant seals, Mirounga leonina, on Macquarie Island, Australia. The virus displayed classic alphavirus ultrastructure and appeared to be serologically different from known Australasian alphaviruses. Nearly all Macquarie Island elephant seals tested had neutralizing antibodies against the virus, but no virus-associated pathology has been identified, Antarctic Division personnel who have worked extensively with elephant seals showed no serological evidence of exposure to the virus. Sequence analysis illustrated that the southern elephant seal (SES) virus segregates,vith the Semliki Forest group of Australasian alphaviruses. Phylogenetic analysis of known alphaviruses suggests that alphaviruses might be grouped according to their enzootic vertebrate host class, The SES virus represents the first arbovirus of marine mammals and illustrates that alphaviruses can inhabit Antarctica and that alphaviruses can be transmitted by lice.

Carpal glands in feral pigs (Sus domesticus) in tropical lowland rainforest in north-east Queensland, Australia

Carpal glands (CG) of 105 feral pigs Sus domesticus, caught in the tropical lowland rainforest in northeast Queensland, Australia, between 1999 and 2004, were investigated to examine their function in chemical communication between animals, and their histology. Female feral pigs show significantly larger CG on the right leg than on the left leg while there were no side-specific differences in males. CG on both legs were significantly larger in reproductive than in non-reproductive females, but they did not differ between pregnant and lactating females. The results suggest that CG are involved in the defensive behaviour of reproductive females but not in the identification of the mother by piglets. The area of the left CG was significantly bigger in males compared to females, but no significant difference could be shown for the CG on the right legs. CG of same-aged boars did not change significantly in size throughout the year while females showed smaller CG on the left leg in January and February suggesting that CG may be involved in intra-matriarchal group communication, Same sized and aged boars did not show any correlations between the size of the CG and the weight of their testes and the serum levels of testosterone. These results suggest that CG are not involved in advertising dominance in boars. The histological investigation of CG showed that they are active in feral pigs in the lowland rainforest, consist mainly of apocrine tissue and that their hairs may play a role in distributing secretion.

Parasitic isopods (Gnathia sp.) reduce haematocrit in captive blackeye thicklip (Labridae) on the Great Barrier Reef

Captive Hemigymnus melapterus exposed to large numbers of cultured juvenile parasitic isopods (Gnathia sp.) had significantly lower haematocrit (median 27-62% +/- 5-83% inter-quartile range) than uninfected, control fish (median 32-73% +/- 4-90%). This study is the first to show that juvenile Gnathia sp. reduce total blood volume in H. melapterus. The low haematocrit in infected fish was most likely due to plasma replacing erythrocytes lost as a result of isopods feeding on fish blood. (c) 2005 The Fisheries Society of the British Isles.

Transmission ratio distortion in the human body louse, Pediculus humanus (Insecta : Phthiraptera)

We studied inheritance at three microsatellite loci in eight F-1 and two F-2 families of the body (clothes) louse of humans, Pediculus humanus. The alleles of heterozygous female-parents were always inherited in a Mendelian fashion in these families. Alleles from heterozygous male-parents, however, were inherited in two different ways: (i) in a Mendelian fashion and (ii) in a non-Mendelian fashion, where males passed to their offspring only one of their two alleles, that is, 100% nonrandom transmission. In male body lice, where there was non-Mendelian inheritance, the paternally inherited set of alleles was eliminated. We interpret this pattern of inheritance as evidence for extreme transmission ratio distortion of paternal alleles in this species.

Comparative susceptibility of indigenous and improved pig breeds to Classical swine fever virus infection: Practical and epidemiological implications in a subsistence-based, developing country setting

This study investigated the comparative susceptibility of indigenous Moo Laat and improved Large White/Landrace pig breeds to infection with classical swine fever virus (CSFV) under controlled conditions in the Lao People's Democratic Republic (Lao PDR). The Moo Laat (ML) and Large White/Landrace crossbreed (LWC) pigs were inoculated with a standard challenge strain designated Lao/Kham225 (infectivity titre of 10(2.75) TCID50/ml). The results demonstrated that both the native breed and an improved pig breed are fully susceptible to CSFV infection and the mortality rate is high. LWC pigs demonstrated lower (or shorter) survival times (50% survival time: 11 days), earlier and higher pyrexia and earlier onset of viraemia compared to ML pigs (50% survival time: 18 days). In the context of village-based pig production, the longer time from infection to death in native ML pigs means that incubating or early sick pigs are likely to be sold once an outbreak of CSF is recognized in a village. This increased longevity probably contributes to the maintenance and spread of disease in a population where generally the contact rate is low.