Variation in hatching responses of Nematodirus battus eggs to temperature experiences

Background Nematodirus battus, unlike most other gastrointestinal nematodes, undergoes maturation to an infective larva within the egg. Historically, eggs were considered to require a period of chilling over winter followed by a period of temperature above 10 °C for synchronous hatching to occur (generally in spring). Anecdotal reports of Nematodirus infection out-with spring in veterinary journals and the farming press suggest that the concentrated pasture abundance of N. battus infective larvae may be changing. In order for control practices to be adapted, and unexpected disease outbreaks to be avoided, it is important to quantify how parasite epidemiology is changing and research the drivers behind it. Method The present study investigated the in vitro hatching response to temperature experiences (with and without a period of chilling) for egg samples of 90 N. battus populations obtained from 73 commercial sheep farms. Six aliquots of larvated eggs were prepared per population, three aliquots were placed at 4 °C for 6 weeks to provide a chill stimulus then incubated at the optimal hatching temperature for the species. The remaining three aliquots of eggs were incubated at the hatching temperature without a prior chill stimulus and the number of hatched larvae was compared between treatments. Results Median hatch rate across all populations with chilling was 45% (95% CI: 42–48%) and without chilling was 4% (95% CI: 2–6%). Inter-population variation in hatching ranged from 0 to 87% of eggs able to hatch in the absence of a chill stimulus, mean non-chill hatching was 13 ± 2% of eggs (mean ± SE). Non-chill hatching rates were greater than chilled hatching rates in seven of the 90 populations tested. Conclusions Clearly, the variation in hatching responses to temperature experience is very large and therefore the seasonality of the parasite may vary not only between regions but also at farm level. In contrast to what previous work has suggested, there was a geographical trend towards higher non-chill hatching in the Northern parts of the UK.

Molecular characterization of a Trichinella spiralis serine proteinase

The aim of this study was to investigate the biological characteristics and functions of a Trichinella spiralis serine proteinase (TsSerp) during larval invasion and development in the host. The full-length TsSerp cDNA sequence was cloned and expressed in Escherichia coli BL21. The results of RT-PCR, IFA and western blotting analyses showed that TsSerp was a secretory protein that was highly expressed at the T. spiralis intestinal infective larva and muscle larva stages and primarily located at the cuticle, stichosome and intrauterine embryos of the parasite. rTsSerp promoted the larval invasion of intestinal epithelial cells (IECs) and the enteric mucosa, whereas an anti-rTsSerp antibody impeded larval invasion; the promotion and obstruction roles were dose-dependently related to rTsSerp and the anti-rTsSerp antibodies, respectively. Vaccination of mice with rTsSerp elicited a remarkable humoral immune response (high levels of serum IgG, IgG1/IgG2a, IgE and IgM), and it also triggered both systemic (spleen) and local intestinal mucosal mesenteric lymph node (MLN) cellular immune responses, as demonstrated by a significant elevation in Th1 cytokines (IFN-γ) and Th2 cytokines (IL-4) after the spleen and MLN cells from vaccinated mice were stimulated with rTsSerp. Anti-TsSerp antibodies participated in the killing and destruction of newborn larvae via ADCC. The mice vaccinated with rTsSerp exhibited a 48.7% reduction in intestinal adult worms and a 52.5% reduction in muscle larvae. These results indicated that TsSerp participates in T. spiralis invasion and development in the host and might be considered a potential candidate target antigen to develop oral polyvalent preventive vaccines against Trichinella infection.

Deteksi Antibodi dan Antigen Cacing Filaria dan Indeks Entomologi Vektor Potensial Filariasis di Kota Langsa Provinsi Aceh

Humans can be infected with filariasis through mosquito bites with filaria worms in infective larva stage (L3). This study was conducted to detect the antibody, antigen, and the entomology index of potential mosquito vectors of filariasis in Langsa City. This research was conducted in Matang Seulimeng Village and Sungai Paoh Firdaus in Langsa City on November 2016 with 600 respondents. To determine the level of exposure to the infection source, a finger blood survey was conducted with a quick check using the rapid diagnostic test (RDT). RDT used is Brugia test to measure antibodies and ICT (Immuno Chromatographic Test) to measure filaria worm antigens. The existence of potential vectors is measured by entomology index, which are mosquito density, relative abundance, frequency of mosquitoes caught and species dominance. As the result, there were no respondent have been found positive for antibodies or filarial worms antigens in their blood. For the vector data, the potential mosquito vector of filariasis in Langsa City is Culex quinquifasciatus (23%) with peak biting activity at 01.00 02.00 pm.

Morphological and Biological Characteristics of Amidostomum Anseris (Nematoda, Amidostomatidae) from Anser anser domesticus

Morphological characteristics were studied in adult and embryonic Amidostomum anseris (Zeder, 1800) obtained from domestic goose Anser anser domesticus Linnaeus, 1758. The studied characters included species-specific morphometric indices of male and female specimens and differential characters of sex-related dimorphism in that species. Stages and periods of embryonic development, and viability of the nematodes were studied at laboratory conditions. Size dimorphism in A. anseris was considerable, females were significantly larger (by 10.09–27.98 %) than males by 11 parameters. Additional metric characters were proposed to enhance effectiveness of differentiation of female and male A. anseris specimens. Under laboratory conditions, embryonic development of A. anseris occurs in four stages: blastomere cleavage; larval formation; formation of non-infective larvae I and II; formation of infective larva III which hatches from the egg. Infective larvae develop at 23 °С in six days, and their viability was up to 78.33 ± 2.08 %.

Peculiarities of Embryonic and Post-Embryonic Development of Оesophagostomum dentatum (Nematoda, Strongylidae) Larvae Cultured in Vitro

Morphometric peculiarities of the development of Оesophagostomum dentatum Rudolphi, 1803 from egg to infective larva were studied under laboratory conditions at various temperatures. The determined optimum temperature for embryonic and post-embryonic development of О. dentatum larvae from domestic pig (Sus scrofa domesticus Linnaeus, 1758) is 22 °С. At this temperature, 81 % of larvae develop to the third stage (L3) on the 10th day. Temperatures of 24 °С and 20 °С are less favorable for the development of the nematode, at those temperatures only 67 and 63 % of larvae, respectively, reached infective stage by the 10th day of cultivation. Embryonic development of О. dentatum eggs is characterized by their lengthening (by 8.87-9.50 %, р < 0.01) and widening (by 6.77-9.35 %, р < 0.05-0.01), and post-embryonic larval development is associated with lengthening (by 4.59-17.33 %, р < 0.01-0.001).

Goblet Cells Proliferation of Duodenum, Jejunum, and Ileum of Laying Hens Immunized with Protein of Excretory-Secretory of Ascaridia galli

This research was conducted in order to examine the goblet cells proliferation in duodenum, jejunum, and ileum of laying hens due to exposured with protein of excretory/secretory (ES) of Ascaridiagalli adult worm. Thirty heads of laying hens were divided in to two groups. The first group was treated with 4,000 infective larva (L2) of A. galli and the second group was immunized with 380µg of ES andfour hours later was challenged with 4000 L2. All treatments were given orally using stainless steelcanule directly to the oesophagus. Data was taken on the 3, 6, 9, 12, and 15 days post immunization(p.i.). The goblet cells were determined by Periodic Acid Schiff (PAS) staining. The result showed that immunization was able to increased goblet cells proliferation significantly at 12 and 15 day p.i. on theduodenum, and at 9, 12, and 15 day p.i. on the jejunum, but goblet cells proliferation did notsignificantly on the ileum. From this result we suggested that ES would beneficial in the strengthen thehost’s defence mechanisms in the intestinal mucosa.Keywords: Ascaridia galli, excretory/secretory, goblet cells

Successive changes in tissue migration capacity of developing larvae of an intestinal nematode,Strongyloides venezuelensis

Infective larvae of an intestinal nematode,Strongyloides venezuelensis, enter rodent hosts percutaneously, and migrate through connective tissues and lungs. Then they arrive at the small intestine, where they reach maturity. It is not known howS. venezuelensislarvae develop during tissue migration. Here we demonstrate that tissue invasion ability ofS. venezuelensislarvae changes drastically during tissue migration, and that the changes are associated with stage-specific protein expression. Infective larvae, connective tissue larvae, lung larvae, and mucosal larvae were used to infect mice by various infection methods, including percutaneous, subcutaneous, oral, and intraduodenal inoculation. Among different migration stages, only infective larvae penetrated mouse skin. Larvae, once inside the host, quickly lost skin penetration ability, which was associated with the disappearance of an infective larva-specific metalloprotease. Migrating larvae had connective tissue migration ability until in the lungs, where larvae became able to settle down in the intestinal mucosa. Lung larvae and mucosal larvae were capable of producing and secreting adhesion molecules.