Flea Infestation in Stray Cats in Jember Regency, East Java, Indonesia: Prevalence, Morphological Characterization and One Health Implications

Stray cats are unowned cats that live freely in environments such as traditional markets, residential areas, and waste disposal sites, where abundant food resources and poor sanitation may increase their exposure to ectoparasites (Kamaruddin et al., 2020; Yanti et al., 2024). Their increasing population, driven by uncontrolled reproduction, abundant food waste, and limited sterilization, together with high humidity and organic waste accumulation, may create favorable conditions for ectoparasite infestation (Rahmiati et al., 2020; Yanti et al., 2024; Siagian et al., 2026). Fleas are among the most common and important ectoparasites of cats and domestic environments because of their high reproductive capacity, ability to feed on multiple host species, and the adverse effects of their bites (Siagian et al., 2026). Flea infestation refers to the presence and establishment of fleas on the external surface of the host (Bossard et al., 2023; Siagian et al., 2023).

Flea infestation represents an important veterinary and public health concern. In cats, flea infestation can cause pruritus, skin irritation, flea allergy dermatitis, hypersensitivity, and anemia in heavy infestations, particularly in young or debilitated animals (Siagian et al., 2023; Bossard et al., 2023). Fleas may also serve as vectors or intermediate hosts of pathogens of veterinary and public health importance, including Dipylidium caninum, Rickettsia felis, Bartonella henselae, Yersinia pestis, and Rickettsia typhi, which may cause dipylidiasis, flea-borne spotted fever, cat-scratch disease, plague, and flea-borne typhus in humans (Cahyani et al., 2020; Canneti et al., 2019; Tsokana et al., 2022; Bossard et al., 2023; Herwanto et al., 2025; Siagian et al., 2026). These concerns underscore the importance of flea surveillance in stray cats, particularly in environments shared by cats, humans, and potential reservoir hosts.

Flea occurrence is influenced by environmental and demographic conditions, including temperature, humidity, host density, and habitat characteristics (Yevstafieva et al., 2021; Siagian et al., 2026). Jember Regency, with approximately 2.62 million inhabitants in 2026, has numerous traditional markets, densely populated settlements, and waste accumulation sites that may facilitate interactions between stray cats, other animals, and humans (Kamaruddin et al., 2020; Badan Pusat Statistik Kabupaten Jember, 2026). Its warm and humid tropical climate may further support flea survival and reproduction (Yevstafieva et al., 2021; Siagian et al., 2026). Previous studies in Indonesia have reported flea infestation among stray cats in several locations. Fauziyah et al. (2020) reported a 74.75% ectoparasite infestation prevalence in stray cats in Surabaya, with C. felis predominating. In Sidoarjo, flea infestation prevalence was 81.8% and 54.5% in two traditional markets, respectively, with C. felis identified as the predominant species (Purwa and Ardiansyah, 2021). More recently, Putri et al. (2026) identified C. felis, C. canis, Ctenocephalides sp., and Pulex irritans in stray cats in Bogor, with an ectoparasite infestation prevalence of 59.76%. These findings indicate geographic variation in flea occurrence and species composition in Indonesia.

However, comprehensive information on flea prevalence, species composition, and spatial distribution among stray cats in Jember Regency remains unavailable. This study provides a comprehensive district-level assessment of flea infestation among stray cats across all 31 districts of Jember Regency. Therefore, this study aimed to determine the prevalence and species composition of fleas infesting stray cats and to characterize their spatial distribution across Jember Regency, East Java, Indonesia. The findings provide baseline epidemiological data for ectoparasite surveillance and contribute to the understanding of flea distribution and its potential veterinary and One Health implications in Indonesia.

This descriptive analytical study investigated flea infestation and species diversity in stray cats across all 31 districts of Jember Regency, East Java, Indonesia, from February to June 2025. All 31 districts comprising Jember Regency were included in the study, with no district excluded. Fleas were processed and identified at the Parasitology Laboratory, Faculty of Health, Medicine, and Life Science, Universitas Airlangga, and Medical Parasitology Laboratory, Universitas Jember. The study protocol was adapted from established flea collection and identification methods (Kamani et al., 2018; Siagian et al., 2023; Azizah et al., 2022; Segura-Tinoco et al., 2025). District names and geographical coordinates are presented in Table 1.

The minimum sample size was calculated using Cochran’s formula for an unknown population, using an assumed prevalence of 50%, a 5% margin of error, and a 95% confidence level, yielding a minimum of 385 stray cats (Mburu, 2026). Sample size was calculated for the overall study population and was not intended to provide a separate minimum sample size for each district. Sampling employed non-probability convenience sampling. Within each district, stray cats were selected based on their availability and accessibility during field surveys, without a predetermined sample quota or minimum sample size for individual districts. Cats were included regardless of sex, age, coat color, or other physical characteristics (Rojas-Saunero et al., 2024). Additional eligible cats encountered during sampling were included whenever possible.

Captured cats were examined for fleas by combing their fur across the entire accessible body surface for 5 min using a fine-toothed comb (Kamani et al., 2018). Pregnancy status was determined by abdominal palpation during physical examination, based on palpable uterine swellings consistent with pregnancy (Mahmood and Younis, 2025). All fleas encountered during the examination were collected using cotton moistened with 70% ethanol and placed in individually labelled sterile 1.5 mL tubes containing 70% ethanol for preservation and subsequent laboratory identification (Siagian et al., 2023; Segura-Tinoco et al., 2025). Each tube was labelled with the host identification, collection location, and collection date and stored at room temperature until laboratory examination.

Table 1: Sampling locations and geographic coordinates of the 31 districts in Jember Regency, East Java, Indonesia.

Permanent slides were prepared following Siagian et al. (2023) with slight modifications. Fleas were cleared in 10% KOH at 60°C for 30 min, dehydrated through 50%, 70%, and 96% ethanol (15 min each), cleared twice in xylene (15 min), and mounted with Entellan®. Specimens were examined under a light microscope and identified to species level using published taxonomic keys based on diagnostic morphological features, including head morphology, genal and pronotal ctenidia, thoracic structures, genitalia and other species-specific diagnostic features, following the identification criteria described by Mathison and Pritt (2014), Schwan et al. (2016), Rust (2017), Ali et al. (2020), Wells and Elston (2020), Yevstafieva et al. (2021), Wei et al. (2022), and Shamsudduha et al. (2025).

Data from physical and microscopic identification were analyzed using quantitative descriptive methods following Sardana et al. (2023). Prevalence was calculated following Njogela et al. (2025) using the formula:

Where Ni is the number of flea-infested cats and Nt is the total number examined. Prevalence was calculated for the overall study area and each district, while flea species composition and distribution were summarized as frequencies and percentages. 95% CI were calculated using the Wilson score method, and Pearson’s chi-square test was used to compare prevalence between sexes and reproduction status, with p< 0.05 considered significant (Sardana et al., 2023). Data were tabulated using Microsoft Excel® 2019 (Microsoft Corporation, Redmond, WA, USA), and spatial distribution maps were generated using Quantum GIS 2019 software (QGIS Development Team).

A total of 470 stray cats were examined across 31 districts of Jember Regency, East Java, Indonesia. Overall, 433/470 (92.1%) of the examined stray cats were flea-positive (95% CI: 89.3-94.2%). Flea infestation was detected in all 31 districts, with district-level prevalence ranging from 77.8% to 100.0% (Figure 1, Table 2). The highest prevalence (100.0%) was recorded in Sumbersari, Gumukmas, Bangsalsari, Semboro, Sukorambi, and Tempurejo, whereas the lowest prevalence was recorded in Rambipuji (77.8%), Mumbulsari (78.6%), and Jenggawah (80.0%).

As shown in Table 3, female cats constituted the majority of the sampled population, accounting for 360/470 (76.6%), while male cats accounted for 110/470 (23.4%). Flea infestation prevalence was 335/360 (93.1%) among female cats (95% CI: 89.9-95.3%) and 98/110 (89.1%) among male cats (95% CI: 81.9-93.6%). Although female cats showed a slightly higher observed prevalence,

Table 2: District-level prevalence of flea infestation and distribution of flea species in stray cats in Jember Regency.

Table 3: Distribution of flea infestation among stray cats by sex and female reproductive status in Jember Regency, East Java, Indonesia.

Note: Confidence intervals were calculated using the Wilson score method. Pearson’s chi-square test was used to assess differences in flea infestation prevalence between male and female cats and between pregnant and non-pregnant female cats.

the difference was not statistically significant (χ²= 1.49, df= 1, p= 0.223). Among the female cats, pregnant cats constituted the majority, accounting for 260/360 (72.2%), while non-pregnant cats accounted for 100/360 (27.8%). Flea infestation prevalence was 241/260 (92.7%) among pregnant cats (95% CI: 88.8-95.5%) and 94/100 (94.0%) among non-pregnant cats (95% CI: 87.5-97.5%). Among flea-positive female cats, 241/335 (71.9%) were pregnant and 94/335 (28.1%) were non-pregnant. The difference in flea infestation prevalence between pregnant and non-pregnant cats was not statistically significant (χ²= 0.19, df= 1, p= 0.662).

Three flea species were identified among the 433 flea-positive cats: Ctenocephalides felis, C. canis, and Xenopsylla cheopis. C. felis was the predominant species, detected in 377/433 flea-positive cats (87.1%) (95% CI: 83.6-89.9%) and recorded in all 31 surveyed districts. Its highest occurrence (100.0%) was recorded in Rambipuji, Ambulu, Kencong, Wuluhan, Mumbulsari, Jombang, Sumberbaru, Jelbuk, Panti, and Silo, whereas the lowest was recorded in Sukorambi (43.8%) (Figure 2, Table 2). C. canis was detected in 177/433 flea-positive cats (40.9%) (95% CI: 36.3-45.6%) and was also recorded across all 31 districts, with proportions ranging from 16.7% to 81.8%. The highest occurrences were recorded in Ambulu (81.8%), Puger (72.7%), Mumbulsari (63.6%), Sukowono (60.0%), Pakusari (58.3%), Jelbuk (58.3%), and Tempurejo (57.1%), while the lowest were observed in Tanggul (16.7%), Kencong (21.4%), Kaliwates (22.2%), and Arjasa (23.1%) (Figure 3, Table 2). In contrast, X. cheopis was the least frequently detected species, occurring in 77/433 flea-positive cats (17.8%) (95% CI: 14.5-21.7%) and showing a more restricted distribution. Its highest occurrences were recorded in Jelbuk (58.3%), Balung (43.8%), Sumberjambe (42.9%), and Umbulsari (40.0%), while it was not detected in Patrang, Rambipuji, Kencong, Wuluhan, Puger, Arjasa, Sukowono, or Panti (Figure 4, Table 2).

Mixed infestations involving more than one flea species were also observed among the examined cats. Among the 433 flea-positive cats, both single and mixed-species flea infestations were observed (Table 4). Single-species infestations were detected in 250 cats (57.7%), comprising Ctenocephalides felis only in 207 cats (47.8%), C. canis only in 24 cats (5.5%), and Xenopsylla cheopis only in 19 cats (4.4%). Mixed-species infestations were observed in 183 cats (42.3%). The most frequent combination was C. felis + C. canis, occurring in 125 cats (28.9%), followed by C. felis + X. cheopis in 30 cats (6.9%) and C. canis + X. cheopis in 13 cats (3.0%). Infestation with all three flea species was observed in 15 cats (3.5%). Overall, C. felis was involved in 377 flea-positive cats (87.1%), followed by C. canis in 177 cats (40.9%) and X. cheopis in 77 cats (17.8%).

Table 4: Distribution of single and mixed-species flea infestations among flea-positive stray cats in Jember Regency, East Java, Indonesia.

The overall flea infestation prevalence of 92.1%, with infestation detected across all 31 districts (Figure 1; Table 2), was higher than that reported in stray cats from Surabaya (74.75%) (Fauziyah et al., 2020), Bogor (59.76%) (Putri et al., 2026), and two traditional markets in Sidoarjo (81.8% and 54.5%) (Purwa and Ardiansyah, 2021). These differences may reflect variations in sampling coverage, location characteristics, cat population dynamics, and sampling approaches. Traditional markets, poor sanitation, and waste accumulation may facilitate close animal contact and flea persistence (Fauziyah et al., 2020; Yevstafieva et al., 2021).

The high prevalence observed in Jember may also be related to local environmental and demographic conditions. In 2026, Jember had a population of 2.625.429 inhabitants and a population density of 792.58 persons/km² (Badan Pusat Statistik Kabupaten Jember, 2026), together with 29 traditional markets, TPA Pakusari, and numerous TPS and TPS 3R facilities (Badan Pusat Statistik, 2018). Such human-modified environments may provide food and shelter for stray cats, supporting persistent cat populations and increasing opportunities for flea transmission (Rahmiati et al., 2020; Yanti et al., 2024; Siagian et al., 2026).

Meteorological conditions may further support flea persistence. Jember recorded annual rainfall of 3,359.6 mm, an average temperature of 25.93°C, and relative humidity of 90.67% in 2025 (Badan Pusat Statistik Kabupaten Jember, 2026). Warm and humid conditions favor the development and survival of flea eggs, larvae, and pupae, potentially supporting sustained flea populations and contributing to the high infestation prevalence observed in stray cats (Moore et al., 2024).

The predominance of female cats in the sampled population (Table 3) may be related to their tendency to form social groups, whereas males generally exhibit more solitary and wider-ranging behavior (Siagian et al., 2026). Despite this difference in population composition, the slightly higher flea infestation prevalence observed in females than males was not statistically significant, suggesting that sex alone may not be an important determinant of flea infestation in this population. The predominance of pregnant females was consistent with previous findings, with pregnant females accounting for 72.2% in the present study, compared with 72.09% reported by Azrizal-Wahid et al. (2019) and 62.6% by Fauziyah et al. (2020). However, flea infestation prevalence was slightly lower in pregnant than non-pregnant females, and the difference was not statistically significant. Increased nutritional demands and altered immune defenses during pregnancy may increase susceptibility to flea infestation (Mohan et al., 2020). In addition, pregnancy-related hormonal and physiological changes may influence grooming and activity patterns, while closer contact with other cats during the reproductive period may increase flea exposure and reinfestation risk (Fauziyah et al., 2020).

The distribution of the three flea species across the 31 districts is summarized in Table 2 and illustrated in Figures 2-4. C. felis was the predominant species, with the highest and most widespread occurrence among the three species (Figure 2; Table 2). Its predominance is consistent with reports from tropical and subtropical regions and may be associated with its broad host range, high reproductive potential, and ecological adaptability (Lawrence et al., 2014; Yanti et al., 2024). However, these factors were not directly assessed in the present study and should therefore be considered possible explanations based on previous literature rather than direct findings of this study. Similarly, Purwa and Ardiansyah (2021) reported C. felis as the predominant flea species infesting stray cats in traditional markets in Sidoarjo Regency.

The widespread occurrence of C. felis across all 31 districts (Figure 2) should be interpreted with consideration of the varying numbers of flea-positive cats sampled in each district. Although 100% occurrence was observed in several districts, including Rambipuji (14/14) and Ambulu (11/11), these estimates were based on relatively small sample sizes and therefore have wider confidence intervals and lower precision. Nevertheless, the consistent detection of C. felis across all 31 districts supports its widespread distribution in the study area. This widespread occurrence may be further supported by the tropical climatic conditions of Jember, characterized by an average annual temperature of approximately 25.93 °C and relative humidity of 90.67% (Badan Pusat Statistik Kabupaten Jember, 2026). Its ability to persist across diverse environments, including residential areas, traditional markets, agricultural land, and other human-modified habitats, may also contribute to its broad distribution (Rust, 2017; Moore et al., 2024). More broadly, flea distribution may be influenced by host preferences, ecological adaptability, and local habitat characteristics, including the availability of alternative hosts (Clark et al., 2018; Deak et al., 2022; Moore et al., 2024).

In contrast, C. canis showed greater spatial variation despite being detected in all 31 districts (Figure 3; Table 2). Although commonly known as the dog flea, C. canis is not strictly host-specific and may infest various mammalian hosts, including cats, while coexisting with other flea species (Deak et al., 2022). Its occurrence on stray cats may therefore be related to ecological overlap between free-roaming dogs and cats, with spatial variation potentially influenced by host community composition and habitat overlap (Clark et al., 2018). However, data on dog abundance, free-roaming dog populations, or the presence of dogs at individual sampling sites were not collected in the present study. Therefore, the role of dog abundance and dog-cat interactions in explaining the observed distribution of C. canis remains speculative. Local environmental conditions may also contribute to its distribution (Moore et al., 2024).

The relatively high occurrence of C. canis in Ambulu, Puger, Mumbulsari, and Tempurejo (Figure 3; Table 2) may be associated with environments that provide food resources and support free-roaming carnivores. In Ambulu, Watu Ulo Beach, where waste from local communities and tourists contributes to substantial waste accumulation, together with traditional markets and transportation facilities, may provide food resources and increase animal movement, potentially facilitating contact between free-roaming dogs and stray cats (Kinanthi et al., 2023). Similarly, the fish auction market in Puger and the densely populated commercial area surrounding Mumbulsari Market may sustain free-roaming carnivores and increase opportunities for cross-host flea transmission (Deak et al., 2022; Budiman et al., 2023). The relatively high occurrence in Tempurejo may likewise reflect interactions between free-roaming dogs and stray cats in plantation, agricultural, and rural environments (Murbarani, 2018; Badan Pusat Statistik Kabupaten Jember, 2026).

Conversely, the lower occurrence of C. canis in Tanggul, Kencong, Kaliwates, and Arjasa (Figure 3; Table 2) may reflect differences in host community composition, habitat overlap, sanitation, and other local environmental characteristics (Azrizal-Wahid et al., 2019; Deak et al., 2022). Because C. canis depends primarily on carnivore hosts rather than environmental reservoirs, its distribution is likely influenced by the composition and abundance of local host communities (Clark et al., 2018; Garcia-Sanchez et al., 2022).

X. cheopis showed the most restricted and heterogeneous distribution among the three flea species (Figure 4; Table 2). This species is primarily associated with synanthropic rodents, particularly Rattus rattus, R. norvegicus, and R. tanezumi, but may temporarily infest other mammals, including cats, dogs, and humans, when host switching occurs (Boyer et al., 2022; Rajamannar et al., 2022). Stray cats may therefore act as incidental hosts when hunting or contacting infested rats or sharing habitats such as traditional markets, waste disposal sites, storage facilities, and densely populated residential areas (Vogel and Schaub, 2025; Siagian et al., 2026).

The heterogeneous distribution of X. cheopis shown in Figure 4 may reflect differences in habitat characteristics, rodent abundance, and the frequency of rodent-cat contact rather than permanent adaptation to feline hosts (Boyer et al., 2022; Bossard et al., 2023; Vogel and Schaub, 2025). Its relatively high occurrence in Jelbuk may be associated with its predominantly agricultural landscape, with rice production reaching 15,222 tons and productivity of 5.91 tons/ha in 2024, while corn had a harvested area of 755 ha (Badan Pusat Statistik Kabupaten Jember, 2025). Such agricultural settings may sustain rodent populations and flea habitats, while stray cats frequenting these environments may consequently encounter flea-infested hosts or contaminated areas (Boyer et al., 2022; Vogel and Schaub, 2025).

Similar conditions may contribute to the occurrence of X. cheopis in Umbulsari, an important agribusiness center with extensive agricultural land and an active traditional market (Indrasti and Rawung, 2021). These environments may provide food and shelter for rodents and facilitate interactions among rats, cats, and humans, increasing opportunities for host switching (Wei et al., 2022; Balasubramanian et al., 2026). In Sumberjambe, the interface between agricultural land and residential settlements may facilitate rodent movement between farmland and human habitation and consequently increase rodent-cat contact (Badan Pusat Statistik Kabupaten Jember, 2026). Likewise, the major traditional market in Balung may provide food waste, storage areas, and shelter for synanthropic rodents, increasing opportunities for stray cats to acquire rodent-associated fleas (Fauziyah et al., 2020; Rajamannar et al., 2022; Vogel and Schaub, 2025).

The absence of X. cheopis from several districts (Figure 4; Table 2) should not necessarily be interpreted as evidence of an absence of rodents or flea populations. The number of cats sampled per district ranged from 12 to 19, which may have limited the probability of detecting this relatively uncommon flea species. Assuming the overall observed prevalence of X. cheopis (17.8%), sampling 12 cats would provide an approximately 90.4% probability of detecting at least one positive cat, indicating that non-detection may still occur even when the species is present. Therefore, the absence of X. cheopis in some districts should be interpreted cautiously. Its low overall prevalence, patchy ecology, differences in rodent abundance, habitat structure, sanitation, rat-cat overlap, and sampling stochasticity may all contribute to non-detection (Clark et al., 2018; Boyer et al., 2022).

Moreover, X. cheopis is less adapted to felids than C. felis and is generally recovered at lower frequencies on cats, more likely reflecting temporary contact with rodent reservoirs (Zaidi et al., 2024). As a nest-associated flea, X. cheopis may spend less time on the host and may be more frequently associated with the host’s nest or surrounding environment, which could further reduce its detection on cats compared with C. felis (Boyer et al., 2022). Therefore, its relatively low occurrence on stray cats may partly reflect differences in host association and detection probability. Its detection on stray cats is more appropriately interpreted as incidental infestation associated with spatial overlap between rats and cats rather than evidence that cats are principal hosts (Clark et al., 2018; Boyer et al., 2022). Host switching remains ecologically plausible because adult fleas may leave their original hosts and survive off-host before locating new ones (Wei et al., 2022). This is consistent with reports of X. cheopis on stray cats and dogs, with higher occurrence on dogs, while C. felis remains predominant on cats (Zaidi et al., 2024; Siagian et al., 2026).

As shown in Table 4, mixed-species infestations accounted for a substantial proportion of flea-positive cats, with C. felis + C. canis being the most frequent combination. This pattern may reflect overlapping habitats and opportunities for contact among cats and other potential hosts. Such co-infestations may be facilitated by shared environments and interactions with dogs and rodents (Rust, 2017; Bossard et al., 2023; Balasubramanian et al., 2026). Shared habitats, host behavior, population dynamics, and host movement may consequently contribute to flea transfer among suitable host species (Clark et al., 2018; Moore et al., 2024).

The occurrence of X. cheopis in both single- and mixed-species infestations is also noteworthy. Its presence alongside C. felis and C. canis may reflect exposure of stray cats to environments shared with other potential hosts, particularly rodents (Rust, 2017; Bossard et al., 2023). Overall, these mixed-species patterns highlight the ecological complexity of flea infestations in stray cats and suggest that flea exposure may be influenced not only by host-specific factors but also by interactions among hosts and their shared environments.

The morphological characteristics observed in this study were consistent with the diagnostic features of the genus Ctenocephalides, particularly the presence of genal and pronotal ctenidia (Yevstafieva et al., 2021). Ctenocephalides felis and C. canis are the two species most commonly associated with cats and dogs (Rust, 2017). Both species possess genal and pronotal ctenidia, with 16 genal teeth and 14-15 pronotal teeth in males and 15-17 in females (Figures 5 and 6A: a1, a2). Therefore, ctenidial tooth number is less useful for species differentiation (Yevstafieva et al., 2021). Sexual identification can be supported by genital morphology, with an aedeagus in males (Figures 5 and 6C: c1) and a spermatheca in females (Figures 5 and 6D: red circle) (Garcia-Sanchez et al., 2022; Hatem and Yasir, 2026).

The most useful characters for distinguishing C. felis from C. canis are related to head morphology and genal spines. C. felis has an elongated head with an angled frons, with head length exceeding twice its height (Figure 5A: red line shape) (Shamsudduha et al., 2025). Its first and second genal spines are approximately equal in length (Figure 5A: a2). C. canis has a shorter head, with length less than twice its height (Figure 6A: red line shape), while the first genal spine is approximately half the length of the second (Figure 6A: a2) (Ali et al., 2020; Hatem and Yasir, 2026).

Differences are also evident in the leg chaetotaxy. The lower marginal area consistenly contains two bristles in C. felis and three in C. canis (Figure 5 and 6A: white circle). The tibiae bear 5-6 notches in C. felis and 7-8 in C. canis (Figure 5 and 6B: b1-b6/b1-b8). The dorsal margin of the hind tibia has one stout bristle in C. felis (Figure 5B: b5) and two in C. canis (Figure 6B: b6, b7). Metatibial chaetotaxy further differs between the species, with arrangements of 2-2-2-2-1-3 in C. felis (Figure 5B: b1-b6) and 2-2-2-2-2-1-1-3 in C. canis (Figure 6B: b1-b8) (Ali et al., 2020).

Xenopsylla cheopis is commonly known as the Oriental rat flea (Wells and Elston, 2020). It is typically brown and approximately 2.5 mm long (Wei et al., 2022). The genus can be readily distinguished from Ctenocephalides by the absence of genal and pronotal ctenidia (Figure 7A: a1, a2) (Wells and Elston, 2020). The mesopleuron is divided by internal sclerotization (Figure 7A: white arrow), which further distinguishes Xenopsylla from Pulex species (Mathison and Pritt, 2014; Hatem and Yasir, 2026).

Species-level identification was supported by genital morphology. Males exhibit a curved, elongated distal aedeagus (Figure 7B), while females possess a characteristic C-shaped spermatheca consisting of a rounded to oval bulga with an elongated, slender, curved hilla (Figure 7C). These genital characteristics are consistent with the diagnostic descriptions of X. cheopis and support its differentiation from other Xenopsylla species (Schwan et al., 2016).

The fleas identified in this study have public health significance as potential vectors or intermediate hosts of zoonotic pathogens. The predominance of Ctenocephalides felis (87.1%) (95% CI: 83.6-89.9%) and C. canis (40.9%) (95% CI: 36.3-45.6%) across all 31 districts is relevant because these species may transmit Rickettsia felis and Bartonella henselae and serve as intermediate hosts of Dipylidium caninum (Cahyani et al., 2020; Canneti et al., 2019; Siagian et al., 2026). R. felis may persist through transovarial transmission and cause non-specific illness resembling murine typhus or dengue fever, while B. henselae causes cat-scratch disease, including potentially severe complications; transmission may occur through infected flea feces contaminating scratches or abrasions (Tsokana et al., 2022; Damayanti and Irawati, 2025).

Xenopsylla cheopis occurred in 17.8% (95% CI: 14.5-21.7%) of flea-positive cats, with higher occurrence in Jelbuk (58.3%), Balung (43.8%), Sumberjambe (42.9%), and Umbulsari (40.0%). As a rodent-associated flea, X. cheopis is an established vector of Yersinia pestis and Rickettsia typhi, while Bartonella spp., R. felis, and Rickettsia asembonensis have also been detected in fleas, although vector competence for some remains uncertain (Eneku et al., 2025; Vogel and Schaub, 2025). Y. pestis is transmitted through regurgitation following bacterial proliferation and biofilm formation in the flea proventriculus, whereas R. typhi is primarily transmitted through infected flea feces entering damaged skin or mucous membranes (Rajamannar et al., 2022; Vogel and Schaub, 2025; Balasubramanian et al., 2026). Murine typhus remains a relevant re-emerging zoonosis in Indonesia (Snellgrove and Goddard, 2024; Herwanto et al., 2025). Fleas may consequently contribute to pathogen maintenance and circulation among animal hosts, vectors, and the environment (Miarinjara et al., 2021; Pauling et al., 2024).

Although cats are not primary reservoirs of Y. pestis or R. typhi, the presence of X. cheopis may indicate ecological overlap among rodents, cats, and humans and facilitate flea movement toward human environments (Clark et al., 2018; Eneku et al., 2025; Vogel and Schaub, 2025). Together, the high flea prevalence (92.1%) and occurrence of multiple flea species support integrated surveillance of flea vectors, animal hosts, and environmental factors within a One Health framework.

Flea infestation in stray cats in Jember Regency was found to be highly prevalent and widely distributed across all 31 districts, with Ctenocephalides felis as the predominant species, followed by C. canis and Xenopsylla cheopis. The widespread occurrence of these flea species highlights their potential importance for animal and public health and indicates the need for continued surveillance and integrated flea-control measures.

Convenience sampling may have introduced selection bias, while the relatively small and unequal number of cats sampled per district (12-19) may have limited the precision of district-level estimates and detection of less common flea species. Sampling sites within districts were also not standardized. Clinical signs, dermatological lesions, post-mortem findings, and flea abundance were not systematically assessed. Species identification relied solely on morphological examination without molecular confirmation. No pathogen screening or human exposure data were collected, limiting direct assessment of flea-borne pathogens and One Health implications. Environmental variables, including temperature, humidity, rodent and dog abundance, and host-environment interactions, were not systematically assessed. Spatial analysis was descriptive without spatial autocorrelation or hotspot analysis. The February-June 2025 sampling period may have introduced temporal variation, and the cross-sectional design limits assessment of temporal trends and causality. Although flea species co-occurrence was recorded, detailed ecological interactions were not assessed. Future studies should use standardized sampling and incorporate temporal, environmental, molecular, pathogen, clinical, and ecological assessments to better characterize flea infestation and its One Health significance.

The authors would like to thank Universitas Airlangga and Universitas Jember for providing laboratory facilities and support for this study. This study received no external funding and was fully self-funded by the authors.

This study provides novel field-based evidence on flea infestation in stray cats across all 31 districts of Jember Regency, East Java, Indonesia, where comprehensive epidemiological data remain limited. By combining infestation prevalence, flea species composition, host sex, and reproductive status, the study characterizes flea infestation patterns at a broad regional scale. The findings establish baseline epidemiological data for Jember Regency and contribute to the limited evidence on flea infestation in stray cats in Indonesia, providing a basis for future surveillance and integrated flea-control strategies relevant to animal and public health.

RAT contributed to conceptualization, data curation, formal analysis, investigation, methodology, software, visualization, and writing-original draft. SNZ and APRD contributed to investigation, data curation, methodology, and writing-original draft. YAS, SA, AMR, AAFP, RHSPL, and FN contributed to investigation. MRF, RDL, FAH, and BRB contributed to resources. RES and FIS contributed to project administration. LWF contributed to supervision, validation, and writing-review and editing.

All procedures were conducted in accordance with accepted animal welfare principles. Fleas were collected non-invasively using gentle handling and minimal restraint. IACUC or equivalent ethical approval was not required because no experimental procedures, treatment, or euthanasia were involved. All cats were returned to their original locations after examination and flea collection. The study complied with Indonesian Law No. 18/2009, as amended by Law No. 41/2014.

All data generated and analyzed in this study are presented in the manuscript. Individual level raw data and QGIS map files are not provided as supplementary materials.

Generative AI tools were not used to create or develop the scientific content of this manuscript. AI assistance was limited to minor language refinement, while all ideas, interpretations, and conclusions were developed and approved by the authors.

The authors have declared no conflict of interest.