Prevention of Lactogenic Toxocara cati Infections in Kittens by Application of an Emodepside/Praziquantel Spot-on (Profender®) to the Pregnant Queen

Human follicular mites: Ectoparasites becoming symbionts

Most humans carry mites in the hair follicles of their skin for their entire lives. Follicular mites are the only metazoans tha continuously live on humans. We propose that Demodex folliculorum (Acari) represents a transitional stage from a host-injuring obligate parasite to an obligate symbiont. Here, we describe the profound impact of this transition on the genome and physiology of the mite. Genome sequencing revealed that the permanent host association of D. folliculorum led to an extensive genome reduction through relaxed selection and genetic drift, resulting in the smallest number of protein-coding genes yet identified among panarthropods. Confocal microscopy revealed that this gene loss coincided with an extreme reduction in the number of cells. Single uninucleate muscle cells are sufficient to operate each of the three segments that form each walking leg. While it has been assumed that the reduction of the cell number in parasites starts early in development, we identified a greater total number of cells in the last developmental stage (nymph) than in the terminal adult stage, suggesting that reduction starts at the adult or ultimate stage of development. This is the first evolutionary step in an arthropod species adopting a reductive, parasitic or endosymbiotic lifestyle. Somatic nuclei show underreplication at the diploid stage. Novel eye structures or photoreceptors as well as a unique human host melatonin-guided day/night rhythm are proposed for the first time. The loss of DNA repair genes coupled with extreme endogamy might have set this mite species on an evolutionary dead-end trajectory.

Cat Respiratory Nematodes: Current Knowledge, Novel Data and Warranted Studies on Clinical Features, Treatment and Control

The nematodes Aelurostrongylus abstrusus, Troglostrongylus brevior and Capillaria aerophila are the most important parasites inhabiting the airways of cats. They are receiving growing attention from academia, pharmaceutical companies and veterinarians, and are now considered a primary cause of respiratory diseases in feline clinical practice and parasitology. In the past few years, several studies have been conducted in both natural and experimental settings to increase knowledge, provide new insights and fill gaps on respiratory parasitoses of cats. Awareness and knowledge of clinical scenarios towards appropriate and timely diagnosis and prompt and efficacious treatment options have become a priority to investigate. At the same time, chemopreventative approaches have been evaluated to assess the geographical spreading of these parasites and the rise in the number of clinical cases in cat populations of different countries. Given the intense accumulation of novel data, this review presents and discusses the state of the art and the latest updates on the clinical features, treatment, and control of major respiratory parasitoses of cats. Moreover, food for thought is also provided with the aim of spurring on new studies in the near future.

Safety evaluation of a novel topical combination of esafoxolaner, eprinomectin and praziquantel, in reproducing female cats

NexGard® Combo, a novel topical endectoparasiticide product for cats, is a combination of esafoxolaner, eprinomectin and praziquantel. The safety of this novel combination administered to females during reproduction and lactation was evaluated per analysis of breeding parameters and adverse reactions observed on females and offspring. Females with successful breeding history were randomized to three groups, a placebo group and groups treated with the novel formulation at 1× or 3× multiples of the maximum exposure dose. Females were dosed at 28-day intervals, at least twice before mating, then during a period including mating, pregnancy, whelping and 56 days of lactation. In the placebo, 1× and 3× groups, 10, 9 and 10 females, respectively completed the study (nine, seven and nine females achieved pregnancy), and were dosed 7.1 times on average. Breeding parameters included success of mating, success of gestation, length of gestation, abortion rate, number of live, dead and stillborn kittens at birth, number of kittens with abnormalities, weight of kittens after birth and at weaning, growth of kittens, proportion of male and female kittens, and proportion of kittens born alive and weaned. No significant adverse reactions related to the novel combination were observed on females and on kittens; no significant and adverse effects on breeding parameters were observed.

Transmammary transmission of Troglostrongylus brevior feline lungworm: a lesson from our gardens

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Transmammary transmission of Troglostrongylus brevior in domestic cats is suggested.

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Snails, rats and lizards play a role in the epidemiology of this feline lungworm.

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Observational parasitology is important in studying events that may occur in small ecological niches around us.

Feline lungworms such as Aerulostrongylus abstrusus and Troglostrongylus brevior are snail-borne pathogens causing respiratory disease in domestic cats. Paratenic hosts such as rodents and reptiles have also been implicated in the epidemiology of these parasites. Although A. abstrusus has been recognized for a long time as the most prevalent lungworm among cats worldwide, T. brevior is of major concern in kittens. Bearing in mind that disease due to T. brevior occurs mainly in pediatric patients younger than 6 months of age, the diagnosis of this parasite in two kittens presenting severe respiratory disease from the garden of one of the authors inspired us to investigate the potential routes of transmission for T. brevior in domestic cats. Of the three queens (A, B and C) that delivered kittens (n = 8), only cat A was positive for T. brevior, presenting her two kittens severe respiratory clinical signs, which lead to the exitus in one of them, 18 days of age. In addition, three kittens, the offspring of queen B, turned to be positive at the coprological examination after suckling from queen A, whereas those from queen C (that suckled only on their own mother) remained negative. A series of coprological, histological and molecular tests were conducted to confirm the presence of T. brevior in the patients as well as in the other cats cohabiting the same garden. Adult nematodes were retrieved from the trachea and bronchi of the dead kitten (kitten 1A), and larvae at the histology of the lung and liver parenchyma associated with bronco pneumonitis and lymphocytic pericholangitis, respectively. Cornu aspersum (n = 60), Eobania vermiculata (n = 30) snails (intermediate hosts) as well as lizards and rats (potential paratenic hosts) were collected from the same garden and processed through tissue digestion and molecular detection. Troglostrongylus brevior larvae were recovered through tissue digestion from two C. aspersum (3.33 %) and it was confirmed by PCR-sequencing approach, which also detected T. brevior DNA in the liver and lungs of one rat and in the coelomatic cavity of one gecko lizard. During the COVID-19 lockdown, when scientists spent more time at home, we grasp the opportunity to decipher T. brevior biology and ecology starting in a small ecological niche, such as the garden of our house. Data herein presented led us to suggest: i) the transmammary transmission of T. brevior in domestic cats; ii) the role of intermediate and paratenic hosts (including reptiles) in the epidemiology of the infection which they transmit; as well as iii) the importance of observational parasitology in studying any event that certainly occurs in small ecological niches, as it could be in our home gardens.

Prevalence of Toxocara in dogs and cats in Africa

Dogs and cats have a close association with humans providing companionship; however, pets are reservoirs of zoonotic pathogens such as Toxocara. Toxocara canis and Toxocara cati are small intestinal nematodes found in canids and felids, respectively. Infected pets shed thousands of eggs resulting in environmental contamination. Toxocara can infect a wide variety of paratenic hosts including humans, rodents, pigs and chickens. Paratenic hosts become infected by ingestion of the infective eggs containing the third stage larvae or ingestion of dormant larvae in animal tissues. Infected humans may develop visceral larval migrans or ocular toxocariasis. Regular anthelmintic treatment and restricted movement of dogs and cats are recommended to control Toxocara environmental contamination. This paper reviews the prevalence and risk factors of Toxocara in dogs and cats in Africa; and pet owners' awareness of canine zoonotic helminths.

Pilot study evaluating the efficacy of a topical formulation containing emodepside and praziquantel in the treatment of natural feline troglostrongylosis

Background

Troglostrongylus brevior, a lungworm usually affecting wild felids, has been recently recorded in a number of cases in domestic cats, mainly in Mediterranean areas. Although feline troglostrongylosis is a severe and life-threatening disease, especially in young cats, treatment options are very limited. The present study evaluated the efficacy and safety of a spot-on formulation containing emodepside 2.1% and praziquantel 8.6% (Profender^®, Bayer), which is licensed for treatment of the more common cat lungworm Aelurostrongylus abstrusus, for the treatment of natural troglostrongylosis.

Methods

Sixteen cats enrolled in the study were 1:1 allocated to two groups, i.e. Group T, treated with Profender^® spot-on on days 0 and 14 (± 2) at the recommended clinical dose, and Group C which remained untreated. After study completion, the control cats received two rescue treatments with Profender^® on days 28 (± 2) and 42 (± 2). The primary efficacy criterion was the absence of T. brevior L1 following treatment. Other efficacy parameters were the quantitative comparison of L1 presence before (baseline) and after treatment in both groups, and the comparison of clinical signs pre- and post-treatment.

Results

In terms of stopping larval shedding, Profender^® showed an efficacy of 97% and 97.5% (arithmetic and geometric means, respectively) for group T, 97.1% and 98.5% for group C after one administration, and 100% for both groups after two doses. Overall, 12 cats showed clinical signs related to T. brevior. Specifically, 9 were clinically affected before treatment while clinical signs appeared after the first treatment in 3 cats. At the end of the study, all symptomatic cats fully recovered with the exception of 3 cats that showed clinical signs similar to those observed at the pre-treatment examination at the end of the study.

Conclusions

This study shows that Profender^® is effective against T. brevior.

Fatal Patent Troglostrongylosis In A Litter of Kittens

Parasitic nematodes affecting the respiratory system of cats are gaining much attention in the scientific community and new knowledge has recently been acquired on their epizootiology, biology, and clinical aspects. In particular, in the past few years different studies have indicated that the metastrongyloid lungworm Troglostrongylus brevior can be vertically transmitted in cats, although information on its basic biology is still poor. The present paper describes a case of troglostrongylosis in a litter of 3 suckling kittens, with a focus on anatomo-pathological and biological features of the infection in 2 of these 3 animals. The third kitten survived the infection and clinical and therapeutic aspects are presented. New insights into the transmission and biology of T. brevior are discussed along with potential strategies for an efficacious treatment and control of this life-threatening parasitosis of cats.

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).