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C Genchi

Publications and source records attributed to C Genchi.

At least 19 recordsLinked to original sources
PubMed2003

Immunoglobulin G antibodies against the endosymbionts of filarial nematodes (Wolbachia) in patients with pulmonary dirofilariasis.

The dog parasite Dirofilaria immitis can infect humans. Patients with pulmonary dirofilariasis were tested for immunoglobulin G (IgG) antibodies against the surface protein of Wolbachia, the bacterial endosymbiont of D. immitis. These patients showed significantly higher IgG titers than healthy individuals from areas in which D. immitis was endemic as well as areas in which it was not endemic. Titration of anti-Wolbachia surface protein IgG could become useful for diagnostic applications.

Animals↗
PubMed2002

Teaching of veterinary parasitology: the Italian perspective.

The curriculum in veterinary medicine in Italy is undergoing important changes, as in the rest of Europe. The 2001 fall semester will mark the beginning of a new format for the degree in veterinary medicine and these changes will obviously affect the teaching of veterinary parasitology. In Italy, veterinary parasitology is usually taught in the third year with a disciplinary approach, similar to that described by Euzéby [Vet. Parasitol. 64 (1996) 21] and Eckert [Vet. Parasitol. 88 (2000) 117]. Approximately 90 h of lectures and 40 h of laboratory are offered and are usually divided into parasitology, followed by parasitic diseases. A more problem-oriented approach to parasitology is offered to fifth-year students within several professional routes (large animal medicine, small animal medicine, hygiene and food safety, etc.), amounting to approximately 15-60 h per student. Indeed, in the last year of study, there are less students and it is possible to present clinical cases and orient the students towards team work and critical discussion. This new curriculum guarantees a reduction in the number of lecture hours and an increase in both laboratory work and personal study, as suggested by the guidelines of the European association of establishment for veterinary education (EAEVE).

Animals↗
PubMed2002

Feline heartworm infection: serological survey of asymptomatic cats living in northern Italy.

Heartworm infection is now recognized as a potential cause of serious disease in cats. Epidemiological studies indicate that in locations where the infection is endemic in the dog, cats are at risk. The aim of this work was to carry out a serological survey for the presence of anti-Dirofilaria immitis antibodies in privately owned, predominantly asymptomatic cats living in different areas of northern Italy in order to determine the distribution of the parasite and the risk of infection in this species. Serum samples from 1045 cats were evaluated using a commercial antibody (Ab) detection kit (Heska Solo Step Filariosi Felina, Heska Corporation) and results were analyzed together with information obtained by questionnaire. Results showed that 16% of all tested cats were positive for anti-D. immitis antibodies, with values ranging from 9 to 27%, depending on location. Male cats and outdoor cats appeared to be at greater risk, with a significantly higher number of positive antibody tests. The results of this study suggest that the risk of exposure with D. immitis in cats is high in northern Italy and suggest that the use of preventive drugs would be advisable in this area endemic for canine heartworm disease.

Age Factors↗
PubMed2002

Tetracycline treatment and sex-ratio distortion: a role for Wolbachia in the moulting of filarial nematodes?

Filarial nematodes harbour intracellular bacteria of the genus Wolbachia. These bacteria are thought to be beneficial to the host nematode. Indeed, tetracycline treatments reduce the population of Wolbachia in filarial worms and have detrimental effects on the nematode. Even though various antibiotic-curing experiments have been performed on filariae, the actual role of Wolbachia in the biology of these nematodes is not yet clear. To address this issue, we designed a first experiment on a model filaria (Brugia pahangi), maintained in the gerbil (Meriones unguiculatus). In this experiment, timing of tetracycline treatment was set on the basis of the larval stage of the nematode. This first experiment showed that 2 weeks of treatment started after the L(4)-L(5) moult of males, but before the moult of females, led to significant sex-ratio distortion of the nematodes. We thus hypothesised that tetracycline interferes with the moult in B. pahangi. To test this hypothesis, we designed a second experiment in which antibiotic treatments were started (1). before the moult of both sexes, (2). after the moult of males but before the moult of females, or (3). after the moult of both sexes. Treatment 1 determined a reduction of worm recovery with no sex bias. Treatment 2 led to a male-biased sex-ratio. Treatment 3 had no effect on either worm recovery or sex-ratio. These results thus support the hypothesis that tetracycline treatment interferes with the L(4)-L(5) moult of B. pahangi. The nematodes recovered from the treated and control animals were examined for the presence of Wolbachia using both immunohistochemistry and real-time PCR. In general, nematodes from treated animals showed a dramatic reduction in Wolbachia content. In one group, Wolbachia depletion, as observed at the end of the treatment, was followed by a rebound to 'normal' values 160 days later. Prospects for antifilarial therapy using Wolbachia-targeted tetracycline treatments should thus take into account the possibility of Wolbachia rebound.

Animals↗
PubMed2001

Sheep oestrosis (Oestrus ovis Linné 1761, Diptera: Oestridae) in Sardinia, Italy.

Oestrosis, the nasal myiasis of sheep and goats, is caused by the larvae of Oestrus ovis L. 1758 (Diptera, Oestridae) that develop from the first to the third stage larva in the nasal cavities and frontal sinuses of affected animals. The authors report the results of an epidemiological study of oestrosis of sheep in Sardinia, Italy. Heads of 6-month to 10-year-old Sardinian sheep (n=566) from 124 free-ranging flocks were examined for the presence and location O. ovis larvae from December 1996 to November 1997. Larvae were collected, counted, and larval stages were identified. O. ovis larvae were found in 100% of examined flocks and in 91% (514/566) of examined sheep. The monthly prevalence ranged from 69% in May to 100% in July. First stage larvae were found in 82% (463) of all heads examined, second stage larvae in 65% (367) and third stage larvae in 10% (56). The majority of sheep harboured first stage larvae, with prevalences of over 80% throughout most of the study period. The prevalence of O. ovis found in this study of Sardinian sheep is the highest reported in the Mediterranean area. The high percentage of first stage larvae found throughout the entire study period may be due to a brief period of decreased rate of larval maturation, in particular in December 1996 (96%) and January-October 1997 (94%). Third stage larvae were consistently present, often however, with extremely low prevalences compared to total larval burden.

Animals↗
PubMed2001

A phylogenetic analysis of filarial nematodes: comparison with the phylogeny of Wolbachia endosymbionts.

Infection with the endosymbiotic bacteria Wolbachia is widespread in filarial nematodes. Previous studies have suggested concordance between the phylogeny of Wolbachia with that of their nematode hosts. However, there is only one published molecular phylogenetic study of filarial species, based on the 5S rRNA gene spacer. The phylogeny proposed by this study is partially incongruent with previous classifications of filarial nematodes, based on morphological characters. Furthermore, both traditional classifications and molecular phylogenies are, in part, inconsistent with the phylogeny of Wolbachia. Here we report mitochondrial cytochrome oxidase I (COI) gene sequences for 11 species of filaria and for another spirurid nematode which was included as an outgroup. In addition, 16S rRNA, wsp and ftsZ gene sequences were generated for the Wolbachia of several filarial species, in order to complete the available data sets and further resolve the phylogeny of Wolbachia in nematodes. We used these data to evaluate whether nematode and Wolbachia phylogenies are concordant. Some of the possible phylogenetic reconstructions based on COI gene were congruent with the phylogeny of Wolbachia and supported the grouping of the rodent filaria Litomosoides sigmodontis with the lymphatic filariae (i.e. Brugia spp. and Wuchereria spp.) and the sister group relationship of Dirofilaria spp. and Onchocerca spp. However, the placement of the Wolbachia-free filaria Acanthocheilonema viteae is ambiguous and dependent on the phylogenetic methods used.

Animals↗
PubMed2001

[Canine dirofilariasis in the canton of Ticino and in the neighboring areas of northern Italy].

The distribution of canine dirofilariosis in Southern Ticino (Switzerland) and in the neighbouring provinces of Varese and Como (Italy) was investigated. Blood samples were collected from 308 dogs which had remained in the local area and were outdoor-housed, older than 1.5 years and had not been treated previously with preventive or microfilaricidal drugs. Microfilariae of Dirofilaria immitis and D. repens were found in 33 (10.7%) and 17 (5.5%) dogs, respectively. Ten more dogs (3.2%) tested positive for circulating antigens. Four infected dogs lived in Southern Ticino: two harboured D. immitis, one D. repens and one had a mixed infection. In addition, 3887 mosquitoes were captured in five sample sites by means of dog-baited traps. Culex pipiens, Aedes geniculatus and Ae. vexans were the most abundant species. Infective stages of D. immitis were observed in local strains of Ae. geniculatus and Cx. pipiens, following engorgement on a microfilaraemic dog and the successive rearing in laboratory conditions. A chemo-prophylactic scheme in four administrations between July and October is recommended for Southern Switzerland.

Animals↗
PubMed2001

Efficacy of moxidectin for the prevention of adult heartworm (Dirofilaria immitis) infection in dogs.

The authors report the efficacy of orally administered moxidectin for the prevention of canine heartworm infection in two endemic areas in northern Italy. Two trials were conducted on a total of 257 dogs, including 137 treated with moxidectin (minimum dose of 3 mcg/kg body weight), 85 with ivermectin (minimum dose 6.6 mcg/kg b.w.) and 35 untreated controls. Results of testing for microfilariae and circulating adult female antigens were negative for all treated dogs at the end of both trials. No adverse reactions to moxidectin were observed. In the study areas, prevalence values for Dirofilaria immitis infection calculated on the basis of the untreated controls and testing dogs which had no preventive treatment in the previous transmission season ranged 23-65%. This study confirms the efficacy and safety of moxidectin in the prevention of adult heartworm infection in dogs.

Animals↗
PubMed2001

Real-time PCR for quantification of the bacterial endosymbionts (Wolbachia) of filarial nematodes.

Filarial nematodes harbour intracellular symbiotic bacteria belonging to the genus Wolbachia. Wolbachia is thought to play an important role in the biology of the nematode. Moreover, Wolbachia appears to be involved in the immunopathogenesis of filariasis and in the onset of the side-effects of antifilarial therapy. Investigations in these research areas require reliable methods to quantify Wolbachia both in nematodes and in vertebrate tissues. To this purpose, we designed a quantitative real-time PCR targeted on the ftsZ gene of the Wolbachia of Brugia pahangi, a model filarial species maintained in gerbils. The method was applied to quantify Wolbachia in Brugia pahangi, from animals with or without tetracycline treatment. Our results show that tetracycline treatment leads to dramatic reduction or clearance of Wolbachia from the nematode. Results obtained from different replicates were reproducible and the method appeared very sensitive compared to other PCR protocols for Wolbachia detection. Real-time PCR is thus an appropriate method for investigations on the biological role of Wolbachia and on the implication of these bacteria in the pathogenesis of filariasis. With slight modifications of the primers and probe, the protocol we have developed could be applied in studies of the human pathogen Brugia malayi and on the model filarial species Litomosoides sigmodontis.

Animals↗
PubMed2000

Antigenic role of the endosymbionts of filarial nematodes: IgG response against the Wolbachia surface protein in cats infected with Dirofilaria immitis.

Filarial nematodes harbour intracellular endosymbiotic bacteria, which have been assigned to the genus Wolbachia. These bacteria appear to play an important role in the pathogenesis of filarial diseases through their lipopolysaccharides. In view of the presence of Wolbachia endosymbionts in the body of filarial nematodes, one might also expect that proteins from these bacteria play an antigenic role in humans and animals affected by filariases. To test this hypothesis, we produced in recombinant form the surface protein WSP and a portion of the cell-cycle protein FTSZ from the Wolbachia of Dirofilaria immitis. Western immunoblot assays were then performed using cat sera to test the immunogenicity of these proteins. Sera were collected from owners' cats, which were either sero-negative or sero-positive for D. immitis and from cats before and after experimental infection with D. immitis. FTSZ was recognized in Western blots by sera from both positive and negative cats and from both uninfected and experimentally infected cats. WSP was recognized only by sera from positive cats and from cats experimentally infected with D. immitis; this protein was not recognized by sera from negative cats and from cats before experimental infection with D. immitis. The results of Western blot assays on WSP thus support the hypothesis that infection with filarial nematodes induces the production of antibodies against Wolbachia proteins.

Amino Acid Sequence↗
PubMed2000

Efficacy of selamectin in the prevention of adult heartworm (Dirofilaria immitis) infection in dogs in northern Italy.

The efficacy of a novel avermectin, selamectin, was evaluated for the prevention of heartworm disease (adult Dirofilaria immitis infection) in 120 dogs (aged 9 months to 13 years at enrolment) presented as veterinary patients. The study was conducted at five veterinary practices in a heartworm hyperendemic region of northern Italy. Dogs were allocated randomly in a 2:1 ratio to treatment with either selamectin or ivermectin. Treatments were administered at monthly intervals for 6 months during the heartworm transmission season (May-November). Selamectin was applied topically in a single spot to the skin on each animal's back at the base of the neck in front of the scapulae as a unit dose that provided at least the minimum recommended dosage of 6mgkg(-1) (range, 6-12mgkg(-1)). Ivermectin (6microgkg(-1) of body weight) was administered orally at monthly intervals, in accordance with the manufacturer's product label recommendations. Study day 0 was defined individually for each dog as the day of first treatment administration. Efficacy was assessed on the basis of the absence of D. immitis microfilariae and adult heartworm (D. immitis) antigen in tests conducted on days 180 and 300. There were no adverse clinical signs arising due to treatment with selamectin and no drug-related mortalities. The prevention rate for D. immitis microfilariae and adult heartworm antigen was 100% for both selamectin and ivermectin. Thus, selamectin administered as a unit dose, providing at least the recommended minimum dosage of 6mgkg(-1), at monthly intervals during the heartworm transmission season was safe and 100% effective in the prevention of heartworm disease in dogs presented as veterinary patients.

Animals↗
PubMed2000

Prevention of experimentally induced heartworm (Dirofilaria immitis) infections in dogs and cats with a single topical application of selamectin.

In a series of six controlled studies (four in dogs, two in cats), heartworm-free dogs and cats were inoculated with Dirofilaria immitis larvae (L(3)) prior to topical treatment with the novel avermectin selamectin or a negative control containing inert formulation ingredients (vehicle). Selamectin and negative-control treatments were administered topically to the skin at the base of the neck in front of the scapulae. In dogs, selamectin was applied topically at dosages of 3 or 6mgkg(-1) at 30 days post-inoculation (PI), or of 3 or 6mgkg(-1) at 45 days PI, or of 6mgkg(-1) at 60 days PI. Cats were treated topically with unit doses providing a minimum dosage of 6mgkg(-1) selamectin at 30 days PI. Of the animals that were treated 30 days PI, some dogs were bathed with water or shampoo between 2 and 96h after treatment, and some cats were bathed with shampoo at 24h after treatment. Between 140 and 199 days PI, the animals were euthanized and examined for adult D. immitis. Adult heartworms developed in all control dogs (geometric mean count, 18.7 worms) and in 88% of control cats (geometric mean count, 2.1 worms). Selamectin was 100% effective in preventing heartworm development in dogs when administered as a single topical dose of 3 or 6mgkg(-1) at 30 days after infection, 3 or 6mgkg(-1) at 45 days after infection, or 6mgkg(-1) at 60 days after infection. Selamectin was 100% effective against heartworm infections in cats when administered as a single topical unit dose of 6mgkg(-1). Bathing with water or shampoo between 2 and 96h after treatment did not reduce the efficacy of selamectin as a heartworm prophylactic in dogs. Likewise, bathing with shampoo at 24h after treatment did not reduce the efficacy of selamectin in cats. These studies demonstrated that, at the recommended dosage and treatment interval, a single topical administration of selamectin was 100% effective in preventing the development of D. immitis in dogs and cats.

Administration, Topical↗
PubMed2000

The efficacy of selamectin in the treatment of naturally acquired infestations of sarcoptes scabiei on dogs.

Selamectin, a novel avermectin, was evaluated for its effect on naturally occurring infestations of Sarcoptes scabiei in 42 dogs. In two controlled and masked laboratory studies conducted in the USA and Italy, infested dogs received treatment with either selamectin (6mgkg(-1); range: 6-12mgkg(-1)) or the vehicle only (negative control). Treatments were administered topically to the skin on each animal's back at the base of the neck in front of the scapulae. Study day 0 was defined as the first day of treatment administration. Dogs were treated on days 0 and 30, and efficacy was assessed by counting viable mites recovered from skin scrapings performed on each dog on days 14, 29 or 30, 44, and 60, and by categorising the clinical signs of canine scabies on the same days. Percentage reductions in geometric mean mite counts for selamectin, compared with vehicle, on days 14, 29 or 30, 44, and 60 were > or =98.1, > or =93.5, 100, and 100%, respectively. Analysis of variance, confirmed by Savage Scores, showed that ln(mite counts+1) values for selamectin-treated dogs were significantly lower (P< or =0.0391) than those for vehicle-treated dogs on all post-treatment assessment days. Clinical signs of scabies were markedly reduced in selamectin-treated dogs, compared with vehicle-treated dogs. Topical administration to the skin in a single spot of a single unit dose of selamectin, or of two unit doses given 1 month apart, each providing at least the recommended minimum dosage of 6mgkg(-1), was highly effective against naturally acquired infestations of S. scabiei in dogs, reducing mite counts by >93% (single dose) and 100% (two doses).

Administration, Topical↗
PubMed2000

The efficacy of selamectin in the treatment of naturally acquired aural infestations of otodectes cynotis on dogs and cats.

The efficacy of a novel avermectin, selamectin, was evaluated against naturally acquired aural infestations of Otodectes cynotis on dogs and cats. In four controlled and masked studies conducted in the USA and Europe, animals were allocated randomly to treatment with either selamectin at a minimum dosage of 6mgkg(-1) (range, 6-12. 5mgkg(-1)) or the vehicle only from the commercial formulation of selamectin (negative control). Treatments were administered topically in a single spot to the skin of each animal's back at the base of the neck in front of the scapulae. Cats were treated on day 0 only, and dogs were treated either on day 0 only or on days 0 and 30. The ears of dogs were examined otoscopically on day 14 for the presence of viable mites. Mite counts were conducted on day 30 for animals that had received one dose and on day 60 for animals that had received two doses. Percentage reductions in geometric mean mite counts for selamectin treatment compared with the vehicle were 100% for all animals on all count days. Analysis of variance, confirmed by Savage Scores, showed that ln(mite count+1) values were significantly (P< or =0.0015) lower for selamectin than for the vehicle for all animals on all count days. Thus, selamectin administered topically at a minimum dosage of 6mgkg(-1) was safe and 100% effective against naturally acquired aural infestations of O. cynotis in dogs and cats after a single dose or after two doses administered 1 month apart.

Administration, Topical↗
PubMed2000

Efficacy of selamectin against experimentally induced and naturally acquired infections of Toxocara cati and Ancylostoma tubaeforme in cats.

The efficacy of selamectin against experimentally induced and naturally acquired infections of adult ascarids (Toxocara cati) and adult hookworms (Ancylostoma tubaeforme) was evaluated in five controlled studies in cats. Two studies evaluated the efficacy of selamectin against both ascarid (natural or induced) and hookworm (induced) infections; two studies evaluated the efficacy of selamectin against single natural infections of T. cati or A. tubaeforme; and the fifth study evaluated the efficacy of selamectin against induced infections of A. tubaeforme. Cats received selamectin topically in unit doses designed to deliver a minimum of 6mgkg(-1). Treatments were applied to the skin on each animal's back at the base of the neck in front of the scapulae. For experimentally induced infections, cats were inoculated orally with approximately 500 embryonated eggs of T. cati 56 days prior to treatment and/or approximately 150-250 larvae (L(3)) of A. tubaeforme 30 or 42 days prior to treatment. For both induced and naturally acquired infections, cats were allocated randomly to treatments (6-12 cats per treatment) on the basis of fecal egg counts to receive either selamectin or a vehicle containing the inert formulation ingredients. In all studies, adult worm counts were performed at necropsy 14 days after the last treatment administration. Against T. cati, a single application of selamectin provided a 100% reduction in the geometric mean number of adult worms for both experimentally induced and naturally acquired infections. Against A. tubaeforme, a single administration of selamectin provided a 99.4% reduction in the geometric mean number of adult worms in cats with natural infections, and an 84.7-99.7% reduction in adult worms in cats with induced infections. Two doses of selamectin administered at monthly intervals provided a 91.9% reduction in the geometric mean number of adult A. tubaeforme worms in cats with experimentally induced infections. The geometric mean numbers of adult worms (T. cati and A. tubaeforme) from selamectin-treated cats were significantly (P< or =0.0018) lower than for vehicle-treated cats in all studies. Thus, a single topical unit dosage providing a minimum dosage of 6mgkg(-1) selamectin was highly effective in the treatment of naturally acquired and experimentally induced infections of T. cati and A. tubaeforme in cats.

Administration, Topical↗
PubMed2000

5 S ribosomal spacer sequences of some filarial parasites: comparative analysis and diagnostic applications.

We have amplified by PCR the sequences of the 5 S ribosomal spacer of Setaria labiatopapillosa and Foleyella furcata. After sequencing, these sequences have been compared with those of Dirofilaria immitis and Dirofilaria repens. Two major goals have been achieved: (i) the establishment of a multiplex PCR-based diagnostic assay, applicable to identify the four species in vertebrate and invertebrate hosts; (ii) the identification, in S. labiatopapillosa and F. furcata, of a canonical spliced leader 1 (SL1) sequence, so confirming that only D. repens, of the filarial parasites so far studied, shows a peculiar SL1 sequence. The PCR assay here developed and the analysis of the 5 S ribosomal spacer, can further improve both epidemiological and molecular analysis of these filarial species.

Animals↗
PubMed2000

wsp gene sequences from the Wolbachia of filarial nematodes.

Wolbachia endosymbiotic bacteria are widespread in arthropods and are also present in filarial nematodes. Almost all filarial species so far examined have been found to harbor these endosymbionts. The sequences of only three genes have been published for nematode Wolbachia (i.e., the genes coding for the proteins FtsZ and catalase and for 16S rRNA). Here we present the sequences of the genes coding for the Wolbachia surface protein (WSP) from the endosymbionts of eight species of filaria. Complete gene sequences were obtained from the endosymbionts of two different species, Dirofilaria immitis and Brugia malayi. These sequences allowed us to design general primers for amplification of the wsp gene from the Wolbachia of all filarial species examined. For these species, partial WSP sequences (about 600 base pairs) were obtained with these primers. Phylogenetic analysis groups these nematode wsp sequences into a coherent cluster. Within the nematode cluster, wsp-based Wolbachia phylogeny matches a previous phylogeny obtained with ftsZ gene sequences, with a good consistency of the phylogeny of hosts (nematodes) and symbionts (Wolbachia). In addition, different individuals of the same host species (Dirofilaria immitis and Wuchereria bancrofti) show identical wsp gene sequences.

Animals↗