Assessing DESS solution for the long-term preservation of nematodes from faecal samples

Preservation of biological samples is a relevant issue for many scientific disciplines. Although traditional preservers, such as formaldehyde or ethanol, imply major disadvantages related to health risks, DNA degradation and distortion of structures, they are widely used. Hence, the search for viable alternatives preserving morphometry and genetics seems necessary. Here we assess the suitability of DESS solution to preserve adult nematodes and their eggs in faeces. Concretely, faecal samples of terrestrial tortoises with oxyurids were used to: (i) compare the 1-month storage efficacy of eggs from different conservation protocols (faeces without preserver at -20 °C, faeces with DESS solution at room temperature, faeces with DESS solution at -20 °C and faeces with ethanol 70% at room temperature); (ii) address morphological nematode identification after 2 years of storage with DESS. We also corroborated that nematode DNA remained viable after 2 years. Overall, our results showed that DESS solution at room temperature is an advisable alternative to conserve both parasite eggs and adult nematodes for morphological identification and genetic purposes. It also offers the advantages of being low-cost, safe and suitable for fieldwork conditions and shipments without refrigeration for nematode preservation.

Geographical variation and factors associated to seroprevalence of canine leishmaniosis in an endemic Mediterranean area

This article retrospectively analyses the spatial distribution and dog- and environmental-level risk factors associated to Leishmania infantum seroprevalence among 807 asymptomatic dogs in the Municipality of Crevillente in Alicante in southeast Spain in 1999. They represented 60% of the dogs in this 103 km2 area, with a human census of 27 034 people and 90% lived in Crevillente town. The estimated seroprevalence (95% confidence interval) in 714 dogs > or =1-year old was 22% (19-25) however; it was 12% (8-15) in town dogs and 0-100% in other administrative zones. High-medium seroprevalence zone clustered along a northeast-southwest fringe and around the town. They comprised the highest and driest inhabited part of the municipality, where farmland was interspersed by residential detached houses, whilst null-low seroprevalence zones included larger farmland extensions and two small rural villages. Predominant vegetation and ground soil type were bush, non-irrigated fruit trees and conglomerate crust and sandstone in medium-high seroprevalence zones and irrigated grassland and fruit trees and colluvial deposits in null-low seroprevalence zones. Random effects logistic regression indicated that the prevalence of infection with L. infantum was higher for dogs sharing residence with infected dogs, increased until 5-6 years old and with body weight and was associated to increasing conglomerate crust and low surface water in the dog's zone of residence. The study confirms that L. infantum infection is endemic in this part of Spain and shows that prevalence can vary significantly within a small area depending on specific demographic and environmental factors conditioning the habitat of the local L. infantum vector, Phlebotomus perniciosus. It suggests similar low-scale variability is present in other geographically variable endemic areas and should be investigated to design Leishmaniosis risk maps and cost-effective, evidence-based, targeted control interventions.

Questionnaire survey on Canine Leishmaniosis in southeastern Spain

A veterinary practitioner's questionnaire survey on Canine Leishmaniosis (CanL) was carried out in southeast Spain to provide information on disease incidence, diagnosis and recommended preventive measures. A third of 101 responding veterinarians reported seeing more than 20 CanL cases during the previous year and clinical signs considered frequent or very frequent included weight loss, areas of exfoliative dermatitis, lymphadenomegaly, kidney dysfunction, onychogryphosis, cutaneous ulcers, anaemia, asthenia and apathy. Almost a third of veterinarians reported diagnosing CanL solely on the basis of lack of response to treatment for other chronic illnesses. The frequency of individual signs did not always reflect their diagnostic value. The majority of veterinarians, considered lymphadenomegaly, exfoliative dermatitis, onychogryphosis, weight loss and epistaxis to be the best disease indicators. However, up to 93% of veterinarians reported using laboratory tests to confirm infection, including indirect (biochemical and antibody assays) and direct (PCR and microscopy) methods. Among recommended measures to prevent CanL, insecticide impregnated collars and topical spot-on capsules were prescribed by 92% and 74% of respondents; however, at least 11% of veterinarians believed existing CanL preventive measures were ineffective. Multivariable statistical analysis indicated that seeing more than 20 CanL cases during the previous year was independently associated with being located in Alicante province, having a rural clientele and recognising that dogs with no other sign but a lack of response to other chronic disease treatments may be infected with CanL. There was a weak association between CanL incidence and rainfall in the months prior to typical sandfly peak abundance.

Epidemiological Study of Non-systemic Parasitism in Dogs in Southeast Mediterranean Spain Assessed by Coprological and Post-mortem Examination

The prevalence and risk factors of non-systemic canine ecto- and endoparasitism and anthelminthic use in Murcia located at the centre of the Spanish Mediterranean coastal arch, was investigated by coprology and necropsy in up to 275 pet, city shelter and stray dogs in 2001-2004. Faecal parasite stages were detected in 25% of dogs. Species frequency was 6-10% for Toxocara canis, Ancylostomatidae spp., Toxascaris leonina and Isospora canis, and 0.4-1% for Trichuris vulpis, Giardia lamblia, and Dipylidium caninum. Logistic regression indicated that the risk of intestinal parasitism was highest for dogs <or=1 year old, in the middle to low weight range and kept at the city shelter. Although risk factors varied according to the species, T. canis was most common in <1 year old and Ancylostomatidae spp. was more prevalent in older dogs. This suggests that the dominant species was Uncinaria spp. and not the more zoonotically important Ancylostoma spp. This was further supported by necropsy findings; however, the degree of agreement between post-mortem and coprological examination for intestinal parasites was generally poor. Necropsy revealed 10%G. lamblia, 12%Taenia spp. 38%D. caninum infections. Fleas, ticks and lice were also found in 38%, 6% and 2% of necropsied stray dogs. These results demonstrate the need for an urgent parasite control programme at the city dog shelter and the need to improve the owner's education on zoonotic risks, the proper use of anthelminthics, and other parasite control practices.

Recombinant vaccine for canine parvovirus in dogs

VP2 is the major component of canine parvovirus (CPV) capsids. The VP2-coding gene was engineered to be expressed by a recombinant baculovirus under the control of the polyhedrin promoter. A transfer vector that contains the lacZ gene under the control of the p10 promoter was used in order to facilitate the selection of recombinants. The expressed VP2 was found to be structurally and immunologically indistinguishable from authentic VP2. The recombinant VP2 shows also the capability to self-assemble, forming viruslike particles similar in size and appearance to CPV virions. These viruslike particles have been used to immunize dogs in different doses and combinations of adjuvants, and the anti-CPV responses have been measured by enzyme-linked immunosorbent assay, monolayer protection assays, and an assay for the inhibition of hemagglutination. A dose of ca. 10 micrograms of VP2 was able to elicit a good protective response, higher than that obtained with a commercially available, inactivated vaccine. The results indicate that these viruslike particles can be used to protect dogs from CPV infection.