Esophageal-Crop Capillariasis and Proventriculus Ventriculus Hystrichisiasis in a Migratory Duck (Anas crecca)

Background: The aim of the present study was to study pathological and parasitological characteristics of simultaneous capillariasis and hystrichiasis in a diseased Anas crecca captured in Mazandaran Province of Iran on Oct 2016. Methods: Parasitology and histopathology techniques were used to detect the parasites of the carcass of the captive common teal. Results: Macroscopically, severe chronic inflammatory reactions and nodular or granuloma formation and irregular thickening of the affected wall of the esophagus, crop, proventrculus and ventriculus were observed. Microscopically, apart from the chronic inflammatory reactions and granuloma formation, in the paraffin sections stained with Harris Hematoxyline and Eosin technique, the characteristics of the mature female and male Capillaria spp. and their barrel-shaped operculated embryonated eggs were found within the tunnels burrowed by the nematode in the hyperplastic stratified squamous epithelium of the inflamed crop and distal portion of the esophagus. The mature female Hystrichis spp. containing oval-shaped, embryonated non-operculated eggs and male parasite were found within the labyrinthus spaces formed in the submucosa granulomas of the ventriculus and proventriculus. Conclusion: Based on the parasitological and pathological studies, the species of the nematode parasites were identified as Capillaria (Thominx) contorta and Hystrichis. tricolor.

Predicting the likelihood and intensity of mosquito infection from sex specific Plasmodium falciparum gametocyte density

Understanding the importance of gametocyte density on human-to-mosquito transmission is of immediate relevance to malaria control. Previous work (Churcher et al., 2013) indicated a complex relationship between gametocyte density and mosquito infection. Here we use data from 148 feeding experiments on naturally infected gametocyte carriers to show that the relationship is much simpler and depends on both female and male parasite density. The proportion of mosquitoes infected is primarily determined by the density of female gametocytes though transmission from low gametocyte densities may be impeded by a lack of male parasites. Improved precision of gametocyte quantification simplifies the shape of the relationship with infection increasing rapidly before plateauing at higher densities. The mean number of oocysts per mosquito rises quickly with gametocyte density but continues to increase across densities examined. The work highlights the importance of measuring both female and male gametocyte density when estimating the human reservoir of infection.

Acanthocephalan size and sex affect the modification of intermediate host colouration

SUMMARYFor trophically transmitted parasites, transitional larval size is often related to fitness. Larger parasites may have higher establishment success and/or adult fecundity, but prolonged growth in the intermediate host increases the risk of failed transmission via natural host mortality. We investigated the relationship between the larval size of an acanthocephalan (Acanthocephalus lucii) and a trait presumably related to transmission, i.e. altered colouration in the isopod intermediate host. In natural collections, big isopods harboured larger worms and had more modified (darker) abdominal colouration than small hosts. Small isopods infected with a male parasite tended to have darker abdominal pigmentation than those infected with a female, but this difference was absent in larger hosts. Female size increases rapidly with host size, so females may have more to gain than males by remaining in and growing mutually with small hosts. In experimental infections, a large total parasite volume was associated with darker host respiratory operculae, especially when it was distributed among fewer worms. Our results suggest that host pigment alteration increases with parasite size, albeit differently for male and female worms. This may be an adaptive strategy if, as parasites grow, the potential for additional growth decreases and the likelihood of host mortality increases.

The fine structures of Cystocaulus ocreatus (Nematoda: Protostrongylidae) and the related lung pathology

In the present study, the fine surface structures of Cystocaulus ocreatus and its worm as well as brood nodules obtained from the lung of Akkaraman sheep are demonstrated by scanning electron and light microscopy. The mouth of the parasite obtained from the worm nodules is located at the anterior tip and encircled by a collar of tissue. The mouth opening appears as three slits conjoined in the shape of a capital case letter Y, creating three lips. The mouth is surrounded by six papillae just behind the collar. The anterior end was similar in both sexes and covered by numerous wrinkles. Female parasite has a bell-shaped pro-vagina. The posterior end of the female parasite was sharply pointed. The male parasite has a bursa. In the worm nodule, curled parasites were enclosed by a capsula and no eggs and larvae of the parasite were observed. In the brood nodule, heavily affected alveoli and bronchioles contained excessive amounts of larvae and eggs.

Immunolocalization of the fatty acid-binding protein Sj-FABPc within adult Schistosoma japonicum

This paper describes the first localization study of the 14·7 kDa fatty acid-binding protein in Schistosoma japonicum (Sj-FABPc) using transmission electron microscopy. A polyclonal antibody raised against recombinant Sj-FABPc was used in combination with a colloidal gold marker to determine the distribution of the protein within adult parasites. Sj-FABPc was localized within lipid droplets below the subtegumental region of the male parasite. Additionally, Sj-FABPc was present in the vitelline droplets of the vitelline glands of female parasites. There were no detectable levels of Sj-FABPc on the surface or within the tegument of male or female parasites. Possible functions of Sj-FABPc within S. japonicum and the relevance of these immunolocalization findings in light of the recent reports that the homologue Sm-FABPc is an important anti-S. mansoni vaccine target molecule are also discussed.

Single sex cercariae ofSchistosoma mansoni, a comparison of male and female infectivity

Over 90% ofSchistosoma haematobiumandS. mansoniinfections show a dominance of male worms in experimental animals. Male: female ratios as high as 5: 1 are common inS. haematobium(Ghana) infections and 1·5: 1 is a typical ratio inS. mansoniinfections. The male parasite seems to be more successful than the female in reaching maturity. To test this theory experiments were set up to compare the infectivity of male and female cercariae.

Some Ecological Attributes of a Pteromalid Parasite and its Housefly Host

The habits and dispersal of the pteromalid parasite Nasonia vitripennis and its housefly host, Musca domestica, and their density relationships were investigated. Male parasite longevity averaged 1.62 days and female longevity 6.96 days. The average number of progeny per female parasite was 139.8. When 25 pairs of parasites were placed with 300 housefly pupae of three sizes, the percentage parasitism was 45.0 for the small (less than 2.0 mm. in diameter), 72.8 for the medium (from 2.0 to 2.5 mm.), and 65.7 for the large (greater than 2.5 mm.). The number of parasites produced per parasitized pupa was 2.20 for the small, 4.30 for the medium, and 6.11 for the large pupae. Increasing the extent of superparasitism produced significantly smaller parasite progeny. A significantly greater normal mortality occurred in small housefly pupae (21.5 per cent) compared with either the medium (6.3 per cent) or the large (5.2 per cent).The parasite dispersed significantly faster when unfed than when fed. Housefly pupae which had been previously exposed to parasites also stimulated the tendency for subsequent parasite emigration. Housefly dispersal was found to be density-dependent under the experimental conditions of the multi-cell population cage.With an increasing parasite-host ratio the rate of parasitization increased until all hosts at a 1 to 1 ratio were parasitized in 24 hours; percentage of parastized hosts producing parasites reached a peak of 71 per cent at the 1 to 2 ratio; and above the 10 to 1 ratio all parasite progeny died due to super-parasitism.