Presence and Associated Factors of Ancylostoma spp. in Domestic Cats from Mexico City, Mexico Associated Factors of Ancylostoma spp. in Domestic Cats

Infections caused by nematodes of the genus Ancylostoma (hookworms) represent a major concern in feline medicine and public health worldwide (Taylor et al., 2016; Bowman, 2021). These hematophagous helminths inhabit the small intestine of their hosts and may cause enteritis, weight loss, malnutrition, and anemia, particularly in kittens and immunocompromised animals (Bowman, 2021; Bowman et al., 2002; Traversa, 2012).

In cats, Ancylostoma tubaeforme and Ancylostoma braziliense are important hookworms. The former is a principal feline hookworm, whereas the latter is associated with cutaneous larva migrans (CLM) in humans (Traversa, 2012; Bowman et al., 2010). Ancylostoma ceylanicum also has zoonotic importance, reinforcing the need to distinguish genus-level detection from species identification (Traub, 2013).

Cutaneous larva migrans occurs when infective larvae actively penetrate human skin following contact with soil or sand contaminated with feces from infected animals, a scenario commonly observed in warm and humid environments (Heukelbach and Feldmeier, 2008). Consequently, hookworm infections in companion animals represent a significant public health concern in urban and peri-urban areas with high densities of dogs and cats (Robertson et al., 2000; Traversa, 2012).

Epidemiological studies have documented the presence of Ancylostoma spp. in feline populations worldwide, with differences related to study populations and diagnostic methods (Zajac and Conboy, 2012; Traversa, 2012). In Mexico, Rodríguez-Vivas et al. (2001) reported Ancylostoma in feline fecal samples submitted to a diagnostic laboratory in Yucatán, whereas Cantó et al. (2013) examined free-roaming cats in Querétaro using postmortem parasitological examination. More recently, Segura-Tinoco et al. (2025) examined feline parasitism across Mexico and assessed associated factors using multivariable analysis. In Mexico City, Iturbe Cossío et al. (2021) previously examined intestinal parasites and owner-reported factors in cats attending a feline medical center. The present investigation therefore does not address an absence of feline clinical studies in the city; its contribution is an Ancylostoma-focused assessment using Mini-FLOTAC in the sampled hospital setting.

Additionally, individual factors such as age, outdoor access, contact with other animals, and management practices may increase the risk of infection in domestic cats (Beugnet et al., 2014; Traversa, 2012).

In this context, epidemiological surveillance of enteroparasites in cats is essential for both veterinary practice and zoonotic disease prevention (Robertson et al., 2000; Beugnet et al., 2014). Coproparasitological diagnosis remains the standard method for detecting hookworm eggs; however, its performance depends on the concentration technique, parasite burden, and operator expertise (Dryden et al., 2005).

The Mini-FLOTAC® technique permits qualitative detection and quantitative evaluation of parasitic elements in feces without the centrifugation required by the original FLOTAC procedure (Cringoli et al., 2017; Cringoli et al., 2010; Barda et al., 2013). Its standardized procedure facilitates reproducible coproparasitological examination.

Therefore, the aim of this study was to determine the frequency of Ancylostoma spp. positivity and explore associated demographic, behavioral, and management factors in fecal samples from domestic cats attending this hospital. The study addresses a defined clinical setting rather than estimating prevalence in the general feline population of Mexico City.

A cross-sectional study was conducted over 24 months at a private veterinary hospital specialized in feline medicine in Mexico City, Mexico. Non-probability convenience sampling was used. Eligible cats resided in Mexico City, had signed owner informed consent, and had fecal samples available. Cats residing outside Mexico City, those whose owners did not sign informed consent, and those without fecal samples were excluded. No a priori sample-size calculation was performed; the study size was determined by the eligible samples available during the study period, yielding an analytical total of 111 fecal samples.

Owners were instructed to collect three consecutive fecal samples per animal, each weighing at least 50 g, in sterile plastic containers while avoiding soil or litter contamination. Samples were transported in insulated coolers at approximately 4 °C and processed separately immediately upon laboratory receipt, without storage. Analysis was completed within 24 h after collection. The 50-g collection quantity was distinct from the 2-g aliquot used for Mini-FLOTAC. Positivity was calculated per fecal sample.

Epidemiological information was obtained using a structured owner questionnaire based on the instrument previously used in the Mexican CEME Gatos study by Iturbe Cossío et al. (2021). This published antecedent provided the methodological basis for the questionnaire used in the present investigation. All owners signed informed consent, and the same veterinarian administered the questionnaire to all participants, providing consistency in interview administration. The questionnaire covered demographic characteristics, health status, and behavioral and management practices. Sex was categorized as female/male; animal contact and outdoor access were recorded as yes/no; owner-performed brushing was recorded as daily, weekly, monthly, or never. Additional variables included bathing, cohabitation with dogs, raw meat consumption, hunting, insect predation, sleeping in the owners’ room, neutering, FeLV/FIV status, vaccination, deworming, and fecal testing. Brushing refers to an owner management practice rather than feline self-grooming. The questionnaire domains and administration are described in Supplementary Description S1.

All samples were analyzed by personnel experienced in the detection of feline parasitic forms at the laboratory of Hospital Veterinario Dermavet. Fecal samples were processed using Mini-FLOTAC®, following the published procedure for fresh cat and dog feces (Cringoli et al., 2017), which expands the general description cited by Capuozzo et al. (2024). A 2-g aliquot was homogenized with 18 mL of sodium chloride flotation solution (FS2; NaCl; specific gravity 1.20), giving a 1:10 dilution. The suspension was mixed in Fill-FLOTAC, filtered through its integrated filter, and used to fill both 1-mL chambers. After 10 min of flotation without centrifugation, the reading disc was rotated approximately 90° and both chamber grids were examined microscopically. At this dilution and 2-mL examination volume, the multiplication factor is 5, corresponding to a theoretical analytical detection limit of 5 eggs per gram. Results were used qualitatively to identify positive samples; egg counts are not reported. Egg detection was reported as Ancylostoma spp.; species-level identification was not performed.

Categorical variables were examined using chi-square tests and unadjusted odds ratios (ORs), with p ≤ 0.05 as the significance threshold. Analyses were performed using JMP 8.0. These univariable analyses explored associations with Ancylostoma spp. sample positivity; no multivariable adjustment was performed. ORs were interpreted in relation to their reference categories and confidence intervals. For sex, the 95% confidence interval included 1, so the evidence was considered inconclusive despite the originally reported p value. Potential confounding, multiple comparisons, and correlation between consecutive samples from the same animal were considered when interpreting the findings.

Ancylostoma spp. eggs were detected in 49 of 111 fecal samples (44.1%). Age was not significantly associated with positivity (p = 0.20). The reported comparison for kittens yielded OR = 2.10 (95% CI: 0.82–5.35). The male-versus-female comparison yielded OR = 2.17 (95% CI: 0.99–4.72; p = 0.04). The 95% confidence interval includes the null value of 1; sex is therefore not classified as an established association. The reported p value and confidence interval differ in their threshold classification; interpretation is therefore conservative.

Outdoor access was not significantly associated with positivity (p = 0.08). Cohabitation with dogs (p = 0.0001) and cohabitation with other cats (p = 0.0001) were associated with sample positivity in the reported univariable comparisons.

Regarding management practices, bathing status (p = 0.0009) and owner-performed brushing status (p = 0.04) were associated with sample positivity. Consumption of raw meat was not significantly associated (p = 0.64). These comparisons do not establish that bathing or grooming prevents infection.

Hunting behavior showed a significant association (p = 0.0003), as did insect predation (p = 0.0001), identifying exploratory associations. Sleeping in the same room as the owners was not significantly associated (p = 0.39).

Neutering status was associated with sample positivity (p = 0.0001). FeLV status (p = 0.20), FIV status (p = 0.25), and up-to-date vaccination status (p = 0.056) did not meet the significance threshold. Time since last deworming and routine coproparasitological testing were reported as nonsignificant. These findings concern unadjusted comparisons and do not establish absence of a biological relationship.

This study confirms that Ancylostoma spp. is present in domestic cats treated at a specialized veterinary hospital in Mexico City, indicating that feline ancylostomiasis remains a relevant issue in small animal clinical practice and public health. According to Taylor et al. (2016), hookworms are among the most important gastrointestinal nematodes in domestic carnivores, while Bowman (2021) highlights their clinical impact, particularly in kittens and immunocompromised individuals, in whom infection may lead to hemorrhagic enteritis, anemia, and deterioration of body condition. The zoonotic relevance, especially of Ancylostoma braziliense, has been widely documented by Traversa (2012), who describes its role in the etiology of cutaneous larva migrans (CLM). Thus, although hookworm infections have traditionally been associated with rural environments, urban settings have increasingly highlighted their epidemiological importance. The observed 44.1% is a frequency among fecal samples rather than an estimate of the proportion of unique cats infected. This distinction is necessary because consecutive samples were collected from each animal.

Mexican studies illustrate differences in the populations and diagnostic methods used to investigate feline parasites. Rodríguez-Vivas et al. (2001) examined diagnostic submissions in Yucatán, and Cantó et al. (2013) investigated cats from an animal control center in Querétaro. The broader survey by Segura-Tinoco et al. (2025) provides national evidence on parasitism and associated factors. Differences from the present results cannot be attributed to climate, indoor conditions, or diagnostic sensitivity alone because the studies differ in recruitment, diagnostic procedures, and denominators. The earlier Mexico City clinical study by Iturbe Cossío et al. (2021) is also a relevant comparator, but findings across studies cannot be treated as interchangeable because the parasites examined and diagnostic approaches differ.

Regarding demographic factors, age was not significantly associated with positivity, although the point estimate for kittens exceeded 2. Young animals can be particularly susceptible to the clinical effects of hookworms (Taylor et al., 2016; Bowman, 2021), but this does not establish an age effect in the present sample. The reported male-versus-female OR was 2.17, with p = 0.04 and a 95% CI of 0.99–4.72. The interval includes the null value of 1 and does not provide conclusive evidence of an association at the 95% confidence level. Behavioral differences are possible explanations, but roaming and contact patterns were not directly tested as mediators, and sex cannot be identified as an independent risk factor.

Cohabitation with dogs and other cats was associated with sample positivity. Shared environmental exposure is a plausible explanation in view of the hookworm life cycle, which includes development of infective larvae in suitable environments (Taylor et al., 2016; Traversa, 2012). However, environmental contamination and infection in cohabiting animals were not measured. The associations therefore do not demonstrate transmission between animals or identify the direction of transmission.

Outdoor access did not reach statistical significance, which does not establish that indoor transmission is equally or more important than outdoor exposure. Hunting and insect predation were associated with positivity. Although some hookworms may use paratenic hosts (Bowman, 2021), this study did not examine prey or insects and cannot demonstrate the acquisition route. Hunting may also be correlated with other exposure and management variables, which were not jointly evaluated.

Hygiene-related variables were associated with sample positivity. Bathing and grooming could reflect broader differences in management or exposure, but the study did not test their preventive effects or measure contamination of the hair coat. Owner-reported behaviors are also susceptible to recall and reporting error. These results should not be interpreted as evidence that bathing or grooming independently prevents intestinal hookworm infection. The questionnaire was based on the published CEME Gatos instrument (Iturbe Cossío et al., 2021), and all interviews were conducted by the same veterinarian.

Neutering status was associated with sample positivity. Neutering is relevant to feline population management, and the reproductive potential of free-roaming cats has been documented (Levy and Crawford, 2004; Nutter et al., 2004). These publications do not establish that neutering prevents hookworm infection. In this study, the observed association may be confounded by sex, age, hunting, or other management factors. Without multivariable analysis, an independent or protective effect of neutering cannot be inferred.

Regarding clinical factors, FeLV and FIV were not significantly associated with sample positivity. The clinical consequences of retroviral infection are well recognized (Little et al., 2020), but the present comparisons do not measure immune function or establish equivalence between viral-status groups.

Time since last deworming was not significantly associated with sample positivity. Reinfection, treatment selection, dosing, and adherence are possible considerations in parasite control (Taylor et al., 2016; ESCCAP, 2021), but these mechanisms were not evaluated here. Consequently, the findings do not demonstrate treatment failure or establish the effectiveness of any deworming regimen.

Up-to-date vaccination status did not meet the significance threshold (p = 0.056). Vaccination and regular health checks form part of preventive veterinary care (Day et al., 2016), but this does not validate vaccination status as a proxy for comprehensive care or establish a relationship with hookworm prevention in this sample.

The use of Mini-FLOTAC® provides a standardized approach to coproparasitological examination (Cringoli et al., 2017). Capuozzo et al. (2024) discuss the FLOTAC family in the context of automated egg detection; their study does not establish the diagnostic sensitivity achieved in these feline samples. No direct comparison with another technique was performed here, so the observed frequency should not be described as a more accurate estimate than those from earlier Mexican studies.

The presence of Ancylostoma spp. eggs supports the relevance of parasite surveillance and owner education within a One Health framework (Robertson et al., 2000; Traversa, 2012). However, genus-level detection does not identify a zoonotic species, and this study did not examine humans or quantify human infection risk.

The convenience sample from a single private hospital limits generalizability. The cross-sectional design does not establish temporality or causation. Although all interviews were conducted by the same veterinarian, owner-reported behaviors remain susceptible to recall and reporting error. Univariable analyses do not control for confounding, and multiple comparisons increase the possibility of chance findings. Consecutive specimens from the same animal may be correlated. The reported frequency therefore describes sample positivity, and the associations should be considered exploratory.

Ancylostoma spp. eggs were detected in 49 of 111 fecal samples (44.1%) from domestic cats attending a private veterinary hospital in Mexico City. Univariable analyses reported associations with cohabitation, hunting, insect predation, hygiene-related variables, and neutering status. The confidence interval for sex included 1; this comparison was inconclusive. These results describe sample positivity and exploratory associations; they do not establish animal-level prevalence, independent risk factors, or causal mechanisms. Convenience recruitment, owner-reported exposures, repeated sampling, and lack of multivariable adjustment limit generalizability and should guide the design of future studies.

The authors thank the participating veterinary hospital for facilitating this study and the cat owners for their cooperation and consent.

This study provides evidence on the occurrence of Ancylostoma spp. infection in cats attending a feline veterinary hospital in Mexico City and its association with demographic characteristics and management practices. These findings contribute local epidemiological information to support parasite prevention and zoonotic risk reduction.

Camilo Romero contributed to the study design. Laura Reyes Clímaco and Ana Quetzalli Marín-Ventura collected and processed the samples. Rafael Heredia performed the statistical analysis. Ariadna Flores and Camilo Romero drafted and revised the manuscript.

The authors declare that no generative AI and AI assisted technology was used in the creation of this manuscript.

The authors have declared no conflict of interest.