Hookworms of feral cats in Florida

Thirty feral cats (Felis catus) from Alachua county (northern Florida) and 30 from Palm Beach county (southern Florida) were examined for hookworms. Two species, Ancylostoma tubaeforme and Ancylostoma braziliense, were identified. Forty-five cats (75%) were infected with A. tubaeforme, with a mean intensity of 48 hookworms per cat. Twenty cats (33%) were infected with A. braziliense, with a mean intensity of 28 worms per cat. The prevalence of A. tubaeforme was greater than that of A. braziliense in Alachua (P=0.002) and Palm Beach (P=0.004) counties. The intensity of A. tubaeforme infections was higher in Palm Beach county than Alachua county (P=0.013). The intensities of A. tubaeforme and A. braziliense were positively correlated (increased together) in Palm Beach county (P=0.011). These hookworms have also been identified in bobcats (Felis rufus), gray foxes (Urocyon cinereoargenteus), and red foxes (Vulpes vulpes) in Florida. The prevalence of A. tubaeforme was significantly greater in feral cats than those reported in bobcats (P<0.001). The prevalence of A. braziliense was significantly greater in feral cats than in those reported in gray foxes (P=0.008). The hookworm that infects Florida panthers and bobcats, A. pluridentatum, was not found.     

The recreational and commercial importance of feral swine in Florida: Relevance to the possible introduction of African swine fever into the U.S.A.

Florida has the largest population of feral swine in the U.S.A. Feral swine have recreational and economic importance to hunters, trappers, taxidermists, and also to dealers who sell feral swine to hunting clubs. Hunters spent over 522 00 man-days hunting feral swine during the 1980–1981 hunting year. They killed nearly 103 000 hogs which they valued at over $58 each, for a total value of nearly $6 million. Trappers caught 25 000 head valued at about $ 700 000, and landowners collected about $1.2 million in hunting lease fees. Taxidermists received about $389 000 in gross income from mounting feral swine. Sales of feral swine to hunting clubs amounted to about $81 000.

Sales of feral swine through commercial livestock auctions were limited to 1620 head valued at only $16 800 in 1980. Thus, feral swine are important to Florida from a recreational standpoint, but not from the perspective of commercial agriculture.

If African swine fever were to enter Florida, there are many socio-economic factors associated with feral swine that must be carefully evaluated for eradication to be successful.     

Seroepidemiology of trichinellosis in Florida swine

Surveys for swine trichinellosis, conducted in Florida using a commercial enzyme-linked immunosorbent assay (ELISA) kit with a modified protocol for screening and Western blot as a definitive test, revealed significantly different seroprevalences of 0.3% (four of 1294 samples) and 2.8% (five of 179 samples) in domestic breeding swine and feral swine, respectively.

Seropositive swine were identified in four of 114 (3.5%) domestic swine herds and in three of six feral swine regions. The location of two domestic herds with seropositive swine within approximately 2 miles of one another, and adjacent to a region where a seropositive feral hog was identified, suggests that a focus of trichinellosis exists in this area. The occurrence of singleton reactors in domestic herds may be explained by the absence of the common modes of transmission and suggests that swine were infected incidentally by feeding on the infected carcasses of small wild mammals or rodents. Although the presence of Trichinella spiralis spiralis isolates cannot be excluded, it is more likely that a sylvatic Trichinella isolate occurs in Florida swine. This conclusion is supported by the low seroprevalence in domestic swine, the failure to detect larvae in domestic or feral swine and the high prevalence in Florida panthers.     

Factors affecting the geographic distribution of pseudorabies (Aujeszky's disease) virus infection among swine herds in Illinois

Data on the geographic distribution of swine herds tested for pseudorabies virus (PRV) in the state of Illinois (USA) were analyzed to determine whether the prevalence of PRV-infected herds was clustered geographically at the county level. Second-order analysis of spatial dependence indicated there was a spatial clustering of counties of high PRV prevalence rates and that this clustering was greater than the observed clustering of counties with a large number of swine herds. The clustering of county PRV prevalence rates was most apparent within a radius of 120 km (on the average, approximately two couties away). The association of county PRV prevalence rates with average herd size, geographic density of swine herds in the country and regional (within 120 km) density of PRV-infected herds was analyzed using multiple linear regression. The primary factor affecting county PRV prevalence rates was the regional PRV density, which interacted with the other model variables. For counties with a low regional density of PRV infection, county PRV prevalence rates charged little with a change in county herd density or average herd size. In contrast, for counties with a high regional density of PRV infection, PRV prevalence within a county increased with increasing average herd size and increasing geographic density of swine herds in the county. The results of the current and previous studies implicate an important role for the geographic proximity of infected herds in the spread of PRV among swine herds.     

Feral Swine Leptospira Seroprevalence Survey in Hawaii,USA, 2007–2009

Leptospirosis is considered the most widespread of zoonotic diseases. It was a notifiable disease in the United States until 1995 and was reinstated to the list of nationally notifiable diseases in 2014. During the time of national surveillance, Hawaii consistently led the nation in reported annual incidence rates. Leptospirosis has remained a reportable disease in Hawaii. Significant changes have been documented since the early 1970s in the predominant serogroup infecting humans in Hawaii: infections due to Icterohaemorrhagiae have declined while infections due to Australis have increased. A recent study from Hawaii demonstrated that Australis was an uncommon infecting serogroup for small mammal hosts. Swine have not been previously studied in Hawaii but are well‐recognized maintenance hosts for leptospires belonging to the Australis serogroup. This study was undertaken to assess the prevalence of Leptospira antibody in feral swine in Hawaii. From January 2007 through December 2009, blood samples were collected opportunistically from feral swine. Using the microscopic agglutination test, we found antibody titres ≥1 : 100 to leptospires in 272 (33.8%) of 804 feral swine. The most frequently reacting serovars to the swine sera were Icterohaemorrhagiae (Icterohaemorrhagiae serogroup) (41.5%) and Bratislava (Australis serogroup) (33.8%). The high seroprevalence and presumptively infecting serovars suggest a link between swine and human infection.     

Identification of Brucella spp. in feral swine (Sus scrofa) at abattoirs in Texas,USA

Various tissues, nasal swabs, urine and blood samples were collected from 376 feral swine at two federally inspected abattoirs in Texas during six separate sampling periods in 2015. Samples were tested for Brucella spp. by culture and serology. Brucella spp. were cultured from 13.0% of feral swine, and antibodies were detected in 9.8%. Only 32.7% of culture‐positive feral swine were also antibody positive, and 43.2% of antibody‐positive feral swine were culture positive. Approximately, the same number of males (14.0%) and females (12.1%) were culture positive, and slightly more males (10.5%) than females (8.7%) were antibody positive. Our results indicate that serology likely underestimates the prevalence of feral swine infected, and that those who come in contact with feral swine should be aware of the symptoms of infection with Brucella spp. to ensure prompt treatment.     

Analysis of the impact of trap-neuter-return programs on populations of feral cats

OBJECTIVE: To evaluate 2 county trap-neuter-return (TNR) programs for feral cat population management via mathematical modeling. DESIGN: Theoretical population model. ANIMALS: Feral cats assessed from 1992 to 2003 in San Diego County, California (n = 14,452), and from 1998 to 2004 in Alachua County, Florida (11,822). PROCEDURE: Data were analyzed with a mathematical Ricker model to describe population dynamics of the feral cats and modifications to the dynamics that occurred as a result of the TNR programs. RESULTS: In both counties, results of analyses did not indicate a consistent reduction in per capita growth, the population multiplier, or the proportion of female cats that were pregnant. CONCLUSIONS AND CLINICAL RELEVANCE: Success of feral cat management programs that use TNR can be monitored with an easily collected set of data and statistical analyses facilitated by population modeling techniques. Results may be used to suggest possible future monitoring and modification of TNR programs, which could result in greater success controlling and reducing feral cat populations.     

Impact of baiting on feral swine behavior in the presence of culling activities

We studied the effects of baiting on feral swine (Sus scrofa) movements and corresponding likelihood of disease spread under real and simulated culling pressure. Our objectives were to determine the proportion of feral swine that used the bait station site, and if baiting of feral swine altered areas of utilization, distances from location centroids to treatment location (control or bait station), and movement rates by survivors during culling activities. We hypothesized that the bait station would increase the sedentary nature of feral swine, thus reducing the potential for dispersal and hence disease dispersal. Our experiment was conducted between February and May 2011 on the Rob and Bessie Welder Wildlife Foundation (WWF) in San Patricio County, Texas. We trapped 83 feral swine and placed GPS collars on 21 animals. We established and maintained a centralized bait station on one side of the WWF from 13 March to 27 April. We conducted population-wide culling activities, including trapping, controlled shooting, drive shooting, and aerial gunning, from 3 to 27 April and removed 143 feral swine (4.6feral swine/km(2)). Areas of utilization did not differ between treatments (control or bait station). However, we found location centroids of bait station site feral swine to be closer to the treatment location than those of control site animals and daily movement rates of bait station site feral swine to be 39% greater than movement rates of control site animals. Based on our observation that only 62% of feral swine trapped in proximity to the bait station used it, we cannot recommend baiting as an alternative to fences for containing animals during culling activities. However, there is value in using bait stations to describe patterns of feral swine movements, facilitate observation, and improve efficacy when conducting removals.     

Efficacy of the Boar-Operated-System to deliver baits to feral swine

Feral swine (Sus scrofa) pose a significant disease threat to livestock and humans. Emerging technologies to reduce feral swine disease transmission risks include fertility control, vaccination, and toxicants. However, for these technologies to be appropriate for field application, a feral swine-specific oral delivery system is needed. We used two field trials to generate information related to appropriate field application of the Boar-Operated-System (BOS?), an oral delivery system designed to provide bait access only to feral swine. Our objectives were to determine whether pre-baiting BOS? units increased bait removal and to evaluate the proportion of feral swine and non-target animals that ingest baits designed to deliver pharmaceuticals through the BOS?. During both trials we used baits housed within 10 BOS? units. We monitored wildlife visitation, bait removal, and ingestion using motion sensing digital photography and baits containing the bait marker tetracycline hydrochloride (TH). During trial 1 we found three of five pre-baited BOS? units were used by feral swine only. Additionally, we found the five BOS? units that were not pre-baited were not used by feral swine or non-target wildlife. During trial 2 we determined bait removal from the BOS? to be reduced by only 10% for feral swine when activated, whereas bait removal from the BOS? by all other wildlife was reduced by 100% when activated. We captured 81 feral swine and 23 raccoons and found 90% and 13% to have TH-marked teeth, respectively. With minor modifications, the BOS? should be considered a valuable tool to be used in feral swine disease management in conjunction with existing technologies.     

Prevalence of infectious diseases in feral cats in Northern Florida

Objectives of this study were to determine prevalence of infection in feral cats in Northern Florida with a select group of infectious organisms and to determine risk factors for infection. Blood samples or sera from 553 cats were tested with a panel of antibody, antigen or PCR assays. Male cats were at higher risk for FIV, Mycoplasma haemofelis, and M. haemominutum. Infection with either FeLV or FIV was associated with increased risk for coinfection with the other retrovirus, M. haemofelis, or M. haemominutum. Bartonella henselae had the highest prevalence and was the only organism that did not have any associated risk for coinfection with other organisms. Feral cats in this study had similar or lower prevalence rates of infections than those published for pet cats in the United States. Thus, feral cats assessed in this study appear to be of no greater risk to human beings or other cats than pet cats.     

Epizootiology of fascioliasis in Montana.

During 1989-1990, the United States Department of Agriculture (USDA) meat inspection records were used to determine the distribution and incidence of liver flukes (Fasciola hepatica and Fascioloides magna) in Montana cattle. Of the cows and bulls slaughtered in USDA-inspected packing plants during a 12 month time period, 17.24% had livers that were condemned because of liver flukes. This was a 12% increase over USDA liver condemnations reported for 1973. Infected animals have been reported from 26 counties in Montana, mostly located in the south-central and western half of the state. Forty-nine percent of the 2.4 million cattle in Montana are raised in these counties. Lymnaeid snail species that may serve as intermediate hosts for Fasciola hepatica were found in most of the counties where liver flukes were reported. The principal vectors believed to be responsible for the transmission of Fasciola hepatica in Montana are species of the genus Fossaria. Stagnicola montanensis and Lymnaea stagnalis, which may serve as intermediate hosts for this parasite have also been collected. A known intermediate host for Fascioloides magna, Stagnicola caperata, was also found in several locations.     

Isolation of Campylobacter from feral swine (Sus scrofa) on the ranch associated with the 2006 Escherichia coli O157:H7 spinach outbreak investigation in California

We report the isolation of Campylobacter species from the same population of feral swine that was investigated in San Benito County, California, during the 2006 spinach-related Escherichia coli O157:H7 outbreak. This is the first survey of Campylobacter in a free-ranging feral swine population in the United States. Campylobacter species were cultured from buccal and rectal-anal swabs, colonic faeces and tonsils using a combination of selective enrichment and antibiotic-free membrane filtration methods. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS, Bruker Daltonics, Inc., Billerica, MA, USA) was used to identify species followed by confirmatory multiplex PCR or 16S rRNA sequencing. Genetic relatedness of Campylobacter jejuni and Campylobacter coli strains was determined by multilocus sequence typing (MLST) and porA allele sequencing. Altogether, 12 (40%) of 30 feral swine gastrointestinal and oral cavity specimens were positive, and six species were isolated: Campylobacter coli, Campylobacter fetus, Campylobacter hyointestinalsis, Campylobacter jejuni, Campylobacter lanienae and Campylobacter sputorum. Campylobacter jejuni subtypes were closely related to MLST sequence type 21 (ST-21) and had identical porA sequences. Campylobacter coli subtypes were unrelated to isolates in the pubMLST/porA database. This feral swine population lived in close association with a 'grassfed' beef cattle herd adjacent to spinach and other leafy green row crop fields. The findings underscore the importance of protecting raw vegetable crops from faecal contamination by wild or feral animals. The study also illustrates a potential risk of Campylobacter exposure for hunters during handling and processing of wild swine meat.     

Diagnostic characterization of a feral swine herd enzootically infected with Brucella.

Eighty feral swine were trapped from a herd that had been documented to be seropositive for Brucella and which had been used for Brucella abortus RB51 vaccine trials on a 7,100-hectare tract of land in South Carolina. The animals were euthanized and complete necropsies were performed. Samples were taken for histopathology, Brucella culture, and Brucella serology. Brucella was cultured from 62 (77.5%) animals. Brucella suis was isolated from 55 animals (68.8%), and all isolates were biovar 1. Brucella abortus was isolated from 28 animals (35.0%), and isolates included field strain biovar 1 (21 animals; 26.3%), vaccine strain Brucella abortus S19 (8 animals, 10.0%), and vaccine strain Brucella abortus RB51 (6 animals, 7.5%). Males were significantly more likely to be culture positive than females (92.9% vs. 60.6%). Thirty-nine animals (48.8%) were seropositive. Males also had a significantly higher seropositivity rate than females (61.9% vs. 34.2%). The relative sensitivity rates were significantly higher for the standard tube test (44.6%) and fluorescence polarization assay (42.6%) than the card agglutination test (13.1%). Lesions consistent with Brucella infection were commonly found in the animals surveyed and included inflammatory lesions of the lymph nodes, liver, kidney, and male reproductive organs, which ranged from lymphoplasmacytic to pyogranulomatous with necrosis. This is the first report of an apparent enzootic Brucella abortus infection in a feral swine herd suggesting that feral swine may serve as a reservoir of infection for Brucella abortus as well as Brucella suis for domestic livestock.     

Human and animal fasciolosis: Coprological survey in Narok,Baringo and Kisumu counties,Kenya

Fasciolosis is caused by digenean trematodes of the genus Fasciola. The principal definitive hosts are cattle, sheep and goats. Humans are infected as accidental hosts. Fasciolosis is one of the major neglected tropical diseases and is considered an emerging zoonotic infection. This study was aimed at determining the prevalence of human and domestic animal fasciolosis in selected counties in Kenya. Stool samples for Fasciola diagnosis were collected from humans and domestic animals and transported to the laboratory at Egerton University and processed using sedimentation technique and examined for the presence of eggs. A total of 272 human samples collected were all negative for Fasciola eggs. A total of 582 domestic animals (cattle [46.0%], sheep [29.9%] and goats [24.1%]) samples collected had overall prevalence of 30.9% for Fasciola infection. There was no significant differences (p > 0.05) between the prevalence of fasciolosis and origin of the animals, sex and season. There was a significant difference (p < 0.05) between the prevalence of fasciolosis and domestic animals, age and body condition. The prevalence of fasciolosis was high in two irrigation schemes which favour the breeding of intermediate host snail and grazing of animals along the irrigation canals where metacercaria of Fasciola parasites could be present on the vegetation. Although human fasciolosis was not detected in this study, the presence of animal fasciolosis can pose public health risk because of its zoonotic nature. Therefore, it is important to introduce measures which would help to reduce the exposure of animals to Fasciola infection.     

Comparative evaluation of an indirect ELISA test for diagnosis of swine cysticercosis employing antigen from Taenia solium and Taenia crassiceps metacestodes

Taenia solium cysticercosis is still a serious public health problem in several countries where poverty and lack of hygiene favor transmission. Because pigs are the primary intermediate hosts, prevalence of porcine cysticercosis is a reliable indicator of active transmission zones. Serological diagnostic methods are important tools for epidemiological studies since they can be applied to living animals on a large scale. Four antigen preparations (cyst fluid and crude) from T. solium and T. crassiceps metacestodes were compared for swine cysticercosis diagnosis by indirect ELISA (IE). Twenty-eight serum samples from swine naturally and experimentally infected by cysticerci of T. solium and 56 serum samples from swine reared in commercial herds were tested. Best results of overall sensitivity were obtained by the use of cyst fluid and crude antigen of T. crassiceps metacestode (100 and 96.4%, respectively). Using homologous antigen preparations we have observed higher specificity percentage (98.2% for cyst fluid and 96. 4% for crude metacestode T. solium antigen). We concluded that sensitivity is of far more importance than specificity for identification of endemic areas in order to prevent transmission to man. We conclude, therefore, that IE performed with cyst fluid antigen of T. crassiceps metacestode is a better tool for that purpose.     

Preferential sexual transmission of pseudorabies virus in feral swine populations may not account for observed seroprevalence in the USA

This paper compares the behavior of two competing models for the transmission of pseudorabies virus in feral swine in the USA. In first model, horizontal (non-sexual) density dependent transmission is the only transmission modality. In the second model, the only transmission modality is sexual transmission between mature males and females. The comparison of model behavior was carried out to test the hypothesis that preferential sexual transmission of PRV in feral swine can account for the seroprevalence observed in the field. The observed range of seroprevalence of PRV in mature feral swine in the USA is consistent with a preferential sexual transmission only if the feral swine mating system is a random mating system or a polygynous system in which there is a relatively large rate of acquisition of new mates. The observed range of seroprevalence of PRV in mature feral swine in the USA is not consistent with a preferential sexual transmission if there is mate guarding. This is important because the National Pseudorabies Surveillance Plan deems monitoring the risk of PRV introduction from feral swine to be a "minor objective" both in terms of the scope of the plan and with respect to the resources allocated. The rationale for this statement was derived from experimental studies, which suggested that the PRV indigenous to feral swine in the USA is preferentially sexually transmitted.     

Prevalence and Characterization of Salmonella Isolated from Feral Pigs Throughout Texas

Feral pigs are one of the most abundant free‐roaming ungulates in the United States, yet their role in the ecology and transmission of foodborne pathogens is poorly understood. Our objectives were to estimate the prevalence of Salmonella shedding among feral pigs throughout Texas, to identify risk factors for infection, and to characterize the isolates. Faecal samples were collected from feral pigs in Texas from June 2013 through May 2015. Standard bacteriologic culture methods were used to isolate Salmonella from samples, and isolates were characterized via serotyping and anti‐microbial susceptibility testing. The prevalence of faecal Salmonella shedding among sampled pigs was 43.9% (194/442), with positive pigs originating from 50 counties. Pigs sampled during fall and summer were significantly more likely to be shedding Salmonella than pigs sampled during winter. High serovar diversity was evident among the isolates, and many of the detected serovars are leading causes of human salmonellosis. The most common serovars were Montevideo (10.0%), Newport (9.1%), and Give (8.2%). Resistance to anti‐microbial agents was rare. The burgeoning feral pig population in the United States may represent an emerging threat to food safety.     

A Mark–Recapture Technique for Monitoring Feral Swine Populations

Techniques to monitor populations of feral swine (Sus scrofa) relative to damage control activities are needed on rangelands. Our objectives were to describe and assess a mark–recapture technique using tetracycline hydrochloride (TH) for monitoring feral swine populations. We established bait stations at study sites in southern and central Texas. During 1 d, we replaced normal soured corn bait with bait containing TH and counted the number of feral swine that consumed bait with observers. We conducted feral swine removal using box-style traps and helicopters, at which time we collected teeth for TH analysis. In southern Texas, we estimated population reduction to be 43%. In central Texas, we estimated population reduction of 31%. Our mark–recapture population monitoring technique would complement programs to manage feral swine populations and damage through lethal control.     

The prevalence and pathogenicity of Chorioptes bovis (Hering, 1845) and Psoroptes cuniculi (Delafond, 1859) (Acari: Psoroptidae) infestations in feral goats in New Zealand

Between October 1976 and January 1980 a total of 368 feral goats was examined in New Zealand for the presence of Chorioptes bovis and 434 for the presence of Psoroptes cuniculi. The seasonal pattern of C. bovis infestation in feral goats was similar to that seen in sheep and cattle. The prevalence of infestation reached 100% in July and August (winter) and declined to 27% in February and March (summer). Fewer goats were infested with P. cuniculi and prevalence of infestation reached a maximum of 41% in July. No goats were found infested in the December and January samples. Chorioptes bovis infestation was independent of the age and sex of hosts. Infestation with P. cuniculi was independent of the sex of the hosts, but older goats were more frequently infested (16%) than younger goats (8.6%). Unilateral infestation with P. cuniculi was more common (74.5%) than bilateral infestation. No severe lesions were associated with C. bovis, but 21.3% of goats with P. cuniculi had the external auditory meatus blocked by waxy material and 12.8% had scabby encrustations on the ears. The importance of goats as a possible source of infestation to domestic animals is discussed.     

Epidemiology of Sarcocystis neurona infections in domestic cats (Felis domesticus) and its association with equine protozoal myeloencephalitis (EPM) case farms and feral cats from a mobile spay and neuter clinic

Equine protozoal myeloencephalitis (EPM) is a serious neurologic disease in the horse most commonly caused by Sarcocystis neurona. The domestic cat (Felis domesticus) is an intermediate host for S. neurona. In the present study, nine farms, known to have prior clinically diagnosed cases of EPM and a resident cat population were identified and sampled accordingly. In addition to the farm cats sampled, samples were also collected from a mobile spay and neuter clinic. Overall, serum samples were collected in 2001 from 310 cats, with samples including barn, feral and inside/outside cats. Of these 310 samples, 35 were from nine horse farms. Horse serum samples were also collected and traps were set for opossums at each of the farms. The S. neurona direct agglutination test (SAT) was used for both the horse and cat serum samples (1:25 dilution). Fourteen of 35 (40%) cats sampled from horse farms had circulating S. neurona agglutinating antibodies. Twenty-seven of the 275 (10%) cats from the spay/neuter clinic also had detectable S. neurona antibodies. Overall, 115 of 123 (93%) horses tested positive for anti-S. neurona antibodies, with each farm having greater than a 75% exposure rate among sampled horses. Twenty-one opossums were trapped on seven of the nine farms. Eleven opossums had Sarcocystis sp. sporocysts, six of them were identified as S. neurona sporocysts based on bioassays in gamma-interferon gene knockout mice with each opossum representing a different farm. Demonstration of S. neurona agglutinating antibodies in domestic and feral cats corroborates previous research demonstrating feral cats to be naturally infected, and also suggests that cats can be frequently infected with S. neurona and serve as one of several natural intermediate hosts for S. neurona.