The vicuna (Vicugna vicugna) as a natural host of Dictyocaulus filaria in Peru

Lungworm infection, or verminous pneumonia, is a parasitic disease that causes serious problems in small and large ruminants. Despite the fact that nematodes of the genus Dictyocaulus in cattle and sheep are the main cause of this disease, there are few studies on the natural infections of South American camelids. For this reason, this study aims to report the natural infection by Dictyocaulus filaria in vicunas (Vicugna vicugna) for the first time. During a shearing season (chaku) in Cuzco, Peru, two accidentally killed adult vicunas were submitted to the IVITA-Marangani research center in Cuzco for their respective necropsies. The tracheas of both vicunas had numerous nematodes, as seen during the necropsy. The nematodes were collected in 70% ethanol and were morphologically identified as D. filaria. Likewise, the DNA of six nematodes was extracted, and the ITS2 region and the 28S rRNA gene were amplified and sequenced. The nucleotide sequences of both genetic markers were up to 100% identical with previously reported D. filaria DNA sequences found in the goat yearlings from Turkey, sheep from Iran, Turkey, and India, and the argali from Uzbekistan, which confirmed the morphological diagnosis. This finding represents the first molecular confirmation of a natural D. filaria infection in a South American camelid. It will be necessary to carry out future studies to know the current situation of verminous pneumonia in domestic and wild South American camelids and to know the negative effects of the disease on them.

Troglostrongylus brevior: a feline lungworm of paediatric concern

The immature immune system of cats in their paediatric age (i.e., first six months of life) favours the establishment of infectious respiratory tract diseases mainly caused by well recognized viruses and bacteria species. Conversely, lungworm infections are less investigated during respiratory disorders in kittens. In the last decade, Troglostrongylus brevior has been found affecting the respiratory tract of cats, along with the better-known Aelurostrongylus abstrusus. Given the scant data available on the epidemiology of feline troglostrongylosis, faecal samples from 575 domestic animals living in three Italian municipalities (i.e., Bari, Messina and Siena) were screened for lungworm infection by Baermann and molecular tecniques. Animals were grouped according to their age as ≤6 months (i.e., paediatric patients), 6-24 months, or >24 months. Paediatric cats were further sub-divided in infant (2-6 weeks), weanling (6-12 weeks) and juvenile (3-6 months). Of the 575 animals tested, 241 (42.0%) were younger than 6 months, 188 (33%) were 6-24-month-old and 146 (25%) were older than 24 months. Lungworm infection was diagnosed in 84 (14.6%) of the examined cats. Of the 49 (20.3%) paediatric animals positive for lungworms, T. brevior was the nematode species most frequently diagnosed (n = 44; 89.8%), followed by A. abstrusus (n = 2; 4.1%), and three cats (6.1%) were co-infected by both species. The diagnosis of T. brevior infection was significantly associated with animals aging ≤6 months (18.2%; P < 0.01) than elder cats. Indeed, the prevalence of infection by T. brevior decreased in animals aging 6-24 months (3.2%) being not detected in cats older than two years. Results of this study indicate that paediatric cats are at higher risk of T. brevior infection compared to adults (P < 0.01).

Lungworm seroprevalence in free-ranging harbour seals and molecular characterisation of marine mammal MSP

Harbour seals (Phoca vitulina) are frequently infected with the lungworms Otostrongylus circumlitus and Parafilaroides gymnurus. The infection is often accompanied by secondary bacterial infections and can cause severe bronchopneumonia and even death in affected animals. Hitherto, the detection of lungworm infections was based on post mortem investigations from animals collected within stranding networks and a valid detection method for live free-ranging harbour seals was not available. Recently, an ELISA was developed for detecting lungworm antibodies in harbour seal serum, using major sperm protein (MSP) of the bovine lungworm, Dictyocaulus viviparus as recombinant diagnostic antigen. To determine lungworm seroprevalence in free-ranging harbour seals, serum was taken from four different seal age groups (n = 313) resulting in an overall prevalence of 17.9% (18.9% of males, 16.7% of females). 0.7% of harbour seals up to six weeks of age were seropositive, as were 89% of seals between six weeks and six months, 53.6% between six and 18 months and 24.2% of seals over 18 months of age. In the 18 months and over age group, seropositive animals showed statistically significant reductions in body weight (P = 0.003) and length (P < 0.001). Sera from lungworm infected harbour seals in rehabilitation (n = 6) revealed that duration of antibody persistence may be similar to that of lungworm infected cattle, but further studies are needed to confirm this. Phylogenetic analyses of MSP sequences of different marine and terrestrial mammal parasitic nematodes revealed that lungworm MSP of the genus Dictyocaulus (superfamily Trichostrongyloidea) is more closely related to metastrongylid marine mammal lungworms than to trichostrongylid nematodes of terrestrial hosts.

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First study on lungworm seroprevalence in live free-ranging harbour seals.

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Total seroprevalence was 17.9%, but age-dependent differences were observed.

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Six weeks to six months old seals showed highest prevalences (89% positives).

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Seropositive adult seals showed significantly reduced body weight and length.

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Phylogenetic tree construction using MSP of marine and terrestrial mammal parasites.