Small islands as potential model ecosystems for parasitology: climatic influence on parasites of feral cats

The influence of climate on parasite distribution has been demonstrated in different regions worldwide. Despite its small size, Gran Canaria (Canary Islands, Spain) constitutes a 'biodiversity laboratory' due to the huge climatic differences between municipalities. Feral cats may represent a threat to biodiversity due to their predatory behaviour. In addition, they may be a source of pathogens zoonotic to humans. To study the climatic/seasonal influence and prevalence of feral cat parasites throughout the island, a total of 290 stool samples from 29 feral cat colonies were analysed following standard concentration protocols (sodium chloride, formol-ether and zinc sulphate). In total, 13 feline parasitic taxa were found, with the most common species being Ancylostoma spp., which, together with Toxocara spp., Toxoplasma gondii and Giardia spp., are considered a concern for human health. Nematodes were the most common parasites in all areas. Nematodes and protozoans were significantly more prevalent in temperate mild (75.0% and 30.0%) than in dry desert areas (29.3% and 18.7%). In contrast, cestodes were significantly more prevalent in dry desert than in temperate mild areas (26.0% and 13.3%). Only protozoans exhibited statistically significant seasonal patterns, mostly in the wet season. Data reported in this study endorse the usage of small and diverse islands such as Gran Canaria to study the climatic influence on parasitic communities in wild/feral animals. Cat colonies require better management to reduce their threat to endemic wildlife, domestic animals and public health, being invasive species that harbour zoonotic parasites.

Measuring, evaluating and improving the effectiveness of invasive predator control programs: Feral cat baiting as a case study

Reducing the impacts of invasive predators is a key objective for conservation managers, livestock producers and human health agencies globally. The efficacy of invasive predator control programs, however, is highly variable. To improve control efficacy, managers require a fundamental understanding of the factors that contribute to the success or failure of a control program. Using a predator baiting program as a case study, we measured the efficacy of baiting as a control tool to significantly reduce feral cat (Felis catus) populations. We used camera traps and cat-borne GPS collars to monitor changes in feral cat populations at a baited site and an unbaited site, using a Before-After, Control-Impact (BACI) design. We also identified five key elements required for a successful baiting program (bait encounter rate, availability, attractiveness, palatability and lethality) and simultaneously measured these to identify areas for potential improvement. Baiting was ineffective at reducing feral cat populations; collared cat mortality was only 11% (1/9), with camera traps revealing negligible reductions in the number of cat detection events (9%), naïve occupancy (15%), and no significant change in the relative abundance of feral cats (F_1,54 = 0.8641, P = 0.357). Several factors contributed to the poor control efficacy. Bait encounter rates were low, with cats active along tracks (where baits were laid) < 4% of the time. Cats encountered only 14% (7/50) of monitored baits, but none were eaten. Initially, baits appeared attractive to cats; however meat ants and desiccation rapidly decreased bait palatability. Bait availability to cats declined rapidly, with 36% of monitored baits (18/50) removed by non-target species within the first 48 h. The mortality of one collared cat and chemical assays confirmed that, on average, each bait contained sufficient 1080 to kill a large (>5 kg) feral cat. Our findings suggest that altering bait deployment patterns, increasing bait densities and improving bait palatability could potentially improve the efficacy of baiting programs to reduce feral cat populations. Our study provides a framework to measure and evaluate the key elements that contribute to efficacy of pest control programs, and to identify opportunities for improving outcomes of future control programs.

Cat ownership and Proximity to Significant Ecological Areas Influence Attitudes Towards Cat Impacts and Management Practices

Cat ownership is increasing globally, representing a growing threat to urban wildlife. Although some cities have policies and strategies for managing owned cats, the companionship value placed on cats makes such management contentious. Prioritizing cat management in urban residential zones adjacent to large significant ecological areas (SEAs; areas designated on the basis of representativeness, threat status or rarity, diversity, connectedness, or uniqueness) could maximize return on management effort. Residents in these areas may place a relatively higher value on nature than residents in suburbs with minimal or no SEAs, and therefore may be comparatively more likely to perceive cats' wildlife impacts as important. We used a quantitative survey to compare SEA and non-SEA suburbs' residents' attitudes towards cat impacts and management in Tāmaki Makaurau-Auckland, Aotearoa-New Zealand. Participants were asked to rate the importance of different feral and owned cat impacts, the importance of feral-cat control in different locations, and various ownership behaviors in terms of acceptability and best practice. SEA suburb residents placed more importance on wildlife predation impacts of feral cats and were more likely to regard 24-h cat confinement as best practice than non-SEA suburb residents. However, we also found that cat ownership and youth were negatively associated with perception of cat impacts, and owners were less likely to accept belled collars and cat confinement than nonowners. Therefore, although targeting SEA adjacent areas for cat management holds promise for reducing resident contention, proximity to such areas is a relatively minor influence for cat owners.

Application of a high-quality, high-volume trap-neuter-return model of community cats in Seoul, Korea

Background

This study was performed to determine the characteristics of community cats that were admitted to trap–neuter–return(TNR) programs and the feasibility of the high-quality, high-volume spay/neuter (HQHVSN) model in Seoul, Korea.

Methods

TNR programs were performed eight times from 2017 to 2018, and a total of 375 community cats from the pilot areas were admitted. The pilot areas were selected regions wherein caregivers voluntarily participated in our TNR program. Each cat was anesthetized, assessed for health status, sterilized, vaccinated against feline viral rhinotracheitis, calicivirus and panleukopenia (FVR-CP), and rabies, and treated with insecticide after surgery. The time from anesthesia to recovery was evaluated to verify the efficiency of surgical time of the program. The TNR program at a local animal hospital and the program in this study were compared to assess the veterinary treatment administered and the cost for each cat.

Results

A total of 375 cats were underwent TNR in this study, including 192 (51.2%) intact females, 180 (48%) intact males, and three (0.8%) sterilized cats. Following surgery, 372 cats (99.2%) were returned to their original locations. Three cats (0.8%) died postoperatively. On average, 21.9% of the cats were pregnant during the TNRs, and the highest percentage of cats (63.9%) were pregnant in March. All cats presented to the TNR program were considered healthy enough to be part of the program after examination. For neutering one animal at a time, similar to conventional TNR ($140), it took 53 ± 16 mins for females and 30 ± 9 mins for males from anesthesia to recovery. In contrast, the standardized procedure can neuter multiple cats simultaneously, similar to the conveyor system, at an estimated rate of 6.8 mins per cat ($45 per female cat, $30 per male cat).

Conclusions

The TNR strategy in Seoul should be implemented by establishing dedicated clinics to concentrate on HQHVSN surgeries of cats. Through this pilot study, we were able to demonstrate that it is possible to effectively apply HQHVSN clinics in Korea. Future studies that perform intensive sterilization in targeted areas are necessary to confirm the efficacy of the TNR strategy.

Voyage of discovery? A comment on Koch et al. "A voyage to Terra Australis: human-mediated dispersal of cats"

The origins of feral cats in Australia may be understood with the help of molecular studies, but it is important that hypotheses be tested with appropriate sampling and methodology. We point out several shortcomings in the analysis by Koch et al. (BMC Evol Biol 15:262, 2015; A voyage to Terra Australis: human-mediated dispersal of cats. Dryad Digital Repository, 2015), present a reanalysis of part of the study and discuss the challenges of elucidating the early history of feral cats.

Study of the effect on shelter cat intakes and euthanasia from a shelter neuter return project of 10,080 cats from March 2010 to June 2014

Cat impoundments were increasing at the municipal San Jose animal shelter in 2009, despite long-term successful low cost sterilization programs and attempts to lower the euthanasia rate of treatable-rehabilitatable impounds beginning in 2008. San Jose Animal Care and Services implemented a new strategy designed to control overall feral cat reproduction by altering and returning feral cats entering the shelter system, rather than euthanizing the cats. The purpose of this case study was to determine how the program affected the shelter cat intakes over time. In just over four years, 10,080 individual healthy adult feral cats, out of 11,423 impounded at the shelter during this time frame, were altered and returned to their site of capture. Included in the 11,423 cats were 862 cats impounded from one to four additional times for a total of 958 (9.5%) recaptures of the previously altered 10,080 cats. The remaining 385 healthy feral cats were euthanized at the shelter from March 2010 to June 2014. Four years into the program, researchers observed cat and kitten impounds decreased 29.1%; euthanasia decreased from over 70% of intakes in 2009, to 23% in 2014. Euthanasia in the shelter for Upper Respiratory Disease decreased 99%; dead cat pick up off the streets declined 20%. Dog impounds did not similarly decline over the four years. No other laws or program changes were implemented since the beginning of the program.

Beyond the disease: Is Toxoplasma gondii infection causing population declines in the eastern quoll (Dasyurus viverrinus)?

Disease is often considered a key threat to species of conservation significance. For some, it has resulted in localised extinctions and declines in range and abundance. However, for some species, the assertion that a disease poses a significant threat of extinction is based solely on correlative or anecdotal evidence, often inferred from individual clinical case reports. While a species' susceptibility to a disease may be demonstrated in a number of individuals, investigations rarely extend to measuring the impact of disease at the population level and its contribution, if any, to population declines. The eastern quoll (Dasyurus viverrinus) is a medium-sized Australian marsupial carnivore that is undergoing severe and rapid decline in Tasmania, its last refuge. Reasons for the decline are currently not understood. Feral cats (Felis catus) may be undergoing competitive release following the ongoing decline of the Tasmanian devil (Sarcophilus harrisii), with cats suppressing eastern quolls through increased predation, competition, exclusion or exposure to diseases such as toxoplasmosis. To investigate the effects of Toxoplasma gondii infection, eastern quoll populations at four sites were regularly screened for the seroprevalence of T. gondii-specific IgG antibodies. Seroprevalence was approximately five times higher at sites with declining quoll populations, and there was a negative association between seroprevalence and quoll abundance. However, T. gondii infection did not reduce quoll survival or reproduction. Despite a high susceptibility to T. gondii infection, eastern quoll populations do not appear to be limited by the parasite or its resultant disease. Significantly higher seroprevalence is a signal of greater exposure to feral cats at sites where eastern quolls are declining, suggesting that increased predation, competition or exclusion by feral cats may be precipitating population declines.

Wildlife disease ecology in changing landscapes: Mesopredator release and toxoplasmosis

Changing ecosystem dynamics are increasing the threat of disease epidemics arising in wildlife populations. Several recent disease outbreaks have highlighted the critical need for understanding pathogen dynamics, including the role host densities play in disease transmission. In Australia, introduced feral cats are of immense concern because of the risk they pose to native wildlife through predation and competition. They are also the only known definitive host of the coccidian parasite, Toxoplasma gondii, the population-level impacts of which are unknown in any species. Australia’s native wildlife have not evolved in the presence of cats or their parasites, and feral cats may be linked with several native mammal declines and extinctions. In Tasmania there is emerging evidence that feral cat populations are increasing following wide-ranging and extensive declines in the apex predator, the Tasmanian devil, from a consistently fatal transmissible cancer.

We assess whether feral cat density is associated with the seroprevalence of T. gondii in native wildlife to determine whether an increasing population of feral cats may correspond to an increased level of risk to naive native intermediate hosts. We found evidence that seroprevalence of T. gondii in Tasmanian pademelons was lower in the north-west of Tasmania than in the north-east and central regions where cat density was higher. Also, samples obtained from road-killed animals had significantly higher seroprevalence of T. gondii than those from culled individuals, suggesting there may be behavioural differences associated with infection. In addition, seroprevalence in different trophic levels was assessed to determine whether position in the food-web influences exposure risk. Higher order carnivores had significantly higher seroprevalence than medium-sized browser species. The highest seroprevalence observed in an intermediate host was 71% in spotted-tailed quolls (Dasyurus maculatus), the largest mammalian mesopredator, in areas of low cat density. Mesopredator release of cats may be a significant issue for native species conservation, potentially affecting the population viability of many endangered species.