Introduction

In 2018, the neighborhoods of Mutange, Bebedouro, Bom Parto, Farol, and Pinheiro in Maceió, Alagoas (AL), were impacted by seismic tremors, fissures, and craters resulting from the exploitation of rock salt, triggering one of the largest environmental crises in Brazil1,2. The earthquake highlighted the risks of mining, leading to the suspension of the mining company’s operations in 2019, the closure of roads and public buildings, the displacement of 55,000 people, and the abandonment of animals3,4,5. During the relocation of families from Mutange in 2020, it was found that 56.8% of the registered animals were abandoned or ran away during the relocation process1,6. Data from the Integra Animal Project corroborate this reality, indicating that 63% of the animals taken in were abandoned, while 3.1% escaped during the move.

Abandonment significantly impacts animal welfare. While some studies suggest that stray animals may maintain an acceptable level of well-being, their vulnerability to physical and mental health problems, as well as exposure to mistreatment, underscores the seriousness of the situation7,8.

In disaster situations, this vulnerability is exacerbated, making animals more susceptible to dehydration and malnutrition due to the scarcity or poor quality of available resources9,10,11. Additionally, they may suffer injuries caused by debris, chemicals, and heated surfaces, as well as aggression from other animals, which become more hostile due to competition for food9,12,13,14.

In this context, free-roaming or abandoned animals are exposed to contaminated environments, which increases the risk of endoparasite transmission and the proliferation of fleas15,16, mites, and ticks. Such conditions also facilitate infections by a wide range of microorganisms, including bacteria, viruses, and fungi, as well as vector-borne pathogens such as Ehrlichia spp. and Babesia spp., and opportunistic agents such as Sporothrix spp.9,12,17,18.

Given these risks, countries that include animals in their contingency plans adopt specific protocols to ensure their safety and well-being, highlighting the need for proper rescue and assistance19. Measures such as selecting appropriate locations for shelter, ensuring environmental conditions similar to the originals, and providing food and specific treatments for each type of affliction are essential to minimize the impacts of these crises on animal.

In this context, to mitigate the impacts of subsidence in Maceió-AL, a set of resolutive actions was developed4,20 in collaboration with the State Public Prosecutor’s Office of Alagoas (MPE-AL), the mining company, and other institutions. As part of this strategy, the Integra Animal Project was created, an initiative of the Research and Extension Group in Equines and Integrative Health at the Federal University of Alagoas, in partnership with the mining company. The project aims to rescue and shelter abandoned animals, raise awareness about mistreatment and responsible pet ownership, and implement methods for capturing and sterilizing stray animals, with a focus on education, public health, and animal welfare.

This study aims to analyze the prevalence of diseases in dogs and cats taken in after the subsidence, identify the main diseases, their origin, and the systems affected by them.

Methods

This action research was approved by the Animal Use Ethics Committee of the Federal University of Alagoas (CEUA/UFAL) under registration number 33/2020 and recorded at the Extension Pro-Rectorate of the Federal University of Alagoas under identification PJ 174-2020.

The study analyzed data from stray and surrendered dogs and cats rescued by the Integra Animal Project between March 2021 and December 2024. Information was obtained from clinical records, hereafter referred to as “cases,” which were periodically reported to the mining company to provide an overview of the animals’ health status. Each case included details about the animal’s clinical condition at entry into the project as well as any diagnoses requiring treatment.

Data recorded in each case included the animal’s name, species, sex, age, address, registration code, responsible person’s name, main clinical complaint, type and origin of the disease, affected organ system, treatment performed, and date (month and year) of care.

Diagnoses were established through clinical evaluation by veterinarians, complemented by ancillary tests when available. Parasitic conditions were primarily identified through physical examination (ectoparasites) or coprological analysis (endoparasites). Infectious and inflammatory diseases were diagnosed based on clinical signs, supported when necessary by laboratory tests such as hematology, serology, or cytology. Neoplasms were detected clinically and confirmed by cytology or histopathology in selected cases. Traumatic, congenital, and acquired conditions were recorded according to clinical and/or surgical notes. Although molecular methods such as PCR or ELISA were not routinely employed, diagnoses followed the standard protocols adopted by the Integra Animal Project veterinary team, ensuring consistency across cases.

Diseases were categorized into the following groups for analytical purposes: infectious (bacterial, viral, and fungal), parasitic (ecto- and endoparasitic), inflammatory, traumatic, neoplastic, congenital, and acquired. Although parasitic diseases are, by definition, infectious, they were analyzed separately due to their high prevalence and distinct epidemiological relevance within the rescued population. This classification was adopted to enhance the clarity of data interpretation and to better illustrate the distribution of disease types observed. Inflammatory conditions included cases characterized by clinical or laboratory evidence of tissue inflammation without confirmation of an infectious, neoplastic, or traumatic cause. Examples included dermatitis of allergic origin, gingivitis, otitis, and nonspecific inflammatory processes described in the medical records.

Ectoparasite infestation was defined as the presence of at least one ectoparasite (fleas, ticks, or mites) detected during clinical examination, regardless of parasite load. The medical records did not include standardized quantification of parasite burden; therefore, all positive findings were classified under the category of ectoparasitic infestation.

Depending on the length of stay in the project, an animal could generate more than one case if a new disease developed or if a chronic condition required periodic monitoring. A case was also obligatorily opened when the animal entered the project or when updates to the sanitary protocol were necessary.

Data were organized, tabulated, and analyzed descriptively. The Chi-square test for goodness of fit was applied to verify the existence of significant differences in categorical data. In addition, generalized linear mixed models (GLMM) with a binomial distribution were used to evaluate the effects of age, species, and ownership status on the occurrence of disease. This study is reported in accordance with the ARRIVE guidelines (Animal Research: Reporting of In Vivo Experiments). All methods were performed in accordance with the relevant guidelines and regulations.

Results

Between March 2021 and December 2024, a total of 6,134 cases were recorded, of which 5,468 (89.1%) involved stray or surrendered and 666 (10.9%) animals with owners (Fig. 1). Among these, 1,676 (27.3%) were dogs and 4,458 (72.7%) were cats, with a monthly average of 133 cases.

Fig. 1
figure 1

Origin and species of animals attended by the integra animal project from March 2021 to December 2024. Integra animal project (2024).

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Of the 6,134 animals attended, 4,539 (74%) were considered healthy, including 3,187 cats (70.2%) and 1,352 dogs (29.8%) (Fig. 2). Females represented 53.7% (2,439/4,539) and males, 46.3% (2,100/4,539), indicating a higher prevalence of healthy females (p < 0.05). Regarding age, 2,209 (48.7%) were up to one year old (1,754 cats and 455 dogs), 1,990 (43.8%) were between one and six years old (1,312 cats and 678 dogs), and 340 (7.5%) were over six years old (121 cats and 219 dogs).

Fig. 2
figure 2

Comparison between healthy and sick animals, both with owners and stray, attended by the Integra animal project from March 2021 to December 2024. Integra animal project (2024).

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Sick animals

Age distribution of disease prevalence differed according to ownership status. Among stray cats, prevalence was 16.2% in kittens (331/2,039), 39.7% in adults (762/1,920), and 60.5% in seniors (107/177). In surrendered cats, prevalence was lower overall: 11.5% in kittens (6/52), 22.6% in adults (45/199), and 28.2% in seniors (20/71). Among stray dogs, prevalence was 17.1% in puppies (92/539), 19.9% in adults (121/609), and 28.8% in seniors (53/184). In surrendered dogs, prevalence was 20.0% in puppies (2/10), 11.2% in adults (24/214), and 26.7% in seniors (32/120).

The Generalized Linear Mixed Model (GLMM) analysis confirmed that disease prevalence varied significantly according to age, species, and ownership status (Table 1). Adult animals had 2.88 times higher odds of being diagnosed with a disease compared to juveniles, while seniors showed an even greater risk, with 4.25 times higher odds than juveniles. Stray animals had 1.35 times higher odds of being diseased compared to surrendered animals. Furthermore, cats were 1.62 times more likely to be diseased than dogs.

Table 1 Results of the generalized linear mixed model (GLMM) of disease risk in dogs and cats by age group, species and responsible.
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Feline species

The main diseases diagnosed in cats were infectious (43.9%–562/1,271), parasitic (23.7%–298/1,271), inflammatory (11.8%–150/1,271), and traumatic (11.6%–147/1,271). Acquired diseases accounted for 7.3% (93/1,271), while congenital and neoplastic diseases were less frequent, at 0.9% (11/1,271) and 0.8% (10/1,271), respectively.

The most prevalent diagnoses, each representing more than 10% of total cases, included Feline Immunodeficiency Virus (FIV) (16.3%–207/1,271), Feline Respiratory Complex (FRC) (16.1%–205/1,271), and parasitic infestations, both ectoparasitic (12.6%–160/1,271) and endoparasitic (12.1%–154/1,271). The prevalence of FRC was slightly higher in surrendered cats (19.7%–14/71) compared with strays (15.9%–191/1,200). Furthermore, FRC affected more females (55.6%) and was predominant in adults (50.2%) and kittens (43.4%). FIV was more frequent in stray adult cats (82.6%), particularly males (75.8%). Ectoparasite infestations mainly affected adult cats (58.8%), while endoparasites were more common in males (56.5%) and adults (69.5%).

Among the moderate diagnoses (5%-10%), otitis (7.7%–98/1,271), wounds (6.9%–88/1,271), and Feline Gingivitis-Stomatitis Complex (FGSC) (5.7%–72/1,271) were highlighted. Otitis was more common in males (64.3%) and adults (73.5%). Wounds, usually resulting from fights or trauma, also predominated in males (65.9%) and adults (65.9%). FGSC followed this pattern, being more prevalent in males (69.4%) and adults (62.5%).

Other diseases were found in the sheltered felines but were less prevalent compared to the others, representing < 5% of the total cases attended (Table 2).

Table 2 Relationship between affected systems and less prevalent diseases in felines.
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Canine species

Among sick dogs, the most common conditions were infectious (34.3%–111/324), parasitic (21.9%–71/324), traumatic (16.4%–53/324), acquired (11.1%–36/324), neoplastic (8.9%–29/324), inflammatory (6.2%–20/324), and congenital (1.2%–4/324). In dogs with owners, the most prevalent diseases—excluding infectious ones were neoplastic (29.3%–17/58), inflammatory (24.1%–14/58), and traumatic (15.5% – 9/58).

Among the most frequent diseases, accounting for more than 5% of the total cases, were conditions caused by ectoparasites (14.2%–46/324), traumatic wounds (10.2%–33/324), otitis (9.6%–31/324), endoparasites (6.2%–20/324), and ehrlichiosis (5.9% – 19/324).

In dogs, infectious and parasitic diseases were therefore among the most frequently recorded conditions. Ehrlichiosis was presented separately from other infectious diseases due to its high prevalence and epidemiological relevance in the studied population, where it is considered one of the most common vector-borne diseases. In addition, parasitic infestations (both ectoparasitic and endoparasitic) and dermatological conditions were highly prevalent, reflecting the environmental exposure and management challenges typical of rescued animals.

Ectoparasite infestations were more common in puppies (80.4%), while traumatic wounds predominated in males (73%) and adults (63.6%). Otitis was more frequently diagnosed in females (77.4%) and adults (71%). For endoparasitoses, there was no significant difference between sexes, but adults (50%; 10/20) and puppies (35%; 7/20) were more affected. Ehrlichiosis affected more females (78.9%), with a higher incidence in seniors (47.4%) and adults (36.8%).

Moderately frequent diseases (2%-5%) included fungal dermatitis (4.9%–16/324), pyoderma (4.6%–15/324), atopic dermatitis, and transmissible venereal tumor (TVT), both with 2.2% (9/324), in addition to periodontal disease, fractures, and neoplasms (2.19%–7/324 each).

Dermatitis and pyoderma were more frequent in females (63.2%), with no significant difference between age groups (p > 0.05). TVT, periodontal disease, fractures, and neoplasms affected males and females equally (50%), being more common in adults (60%) and seniors (30%).

Other diseases were identified in sheltered dogs, but with lower frequency, representing less than 2% of the total cases attended (Table 3).

Table 3 Relationship between affected systems and less prevalent diseases in canines.
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Discussion

The predominance of consultations for stray animals (91.3%, 1,667/1,826) likely reflects the large number of shelters dedicated to this group during the study period. Cats were examined more frequently than dogs, consistent with their greater representation among sheltered animals (80.6%, 1,472/1,826).

Beyond the descriptive patterns, the GLMM analysis confirmed significant effects of age, ownership status, and species on disease prevalence. Compared to juveniles, adult animals were almost three times more likely to present disease, while seniors showed an even greater risk, with more than four times higher odds. This finding is consistent with the expected influence of immunosenescence, cumulative exposure to pathogens, and the greater susceptibility of older animals to chronic and infectious conditions21, 22.

Stray animals also demonstrated higher odds of disease than surrendered animals, a result that can be attributed to their increased exposure to unsanitary environments, nutritional deficiencies, chronic stress, lack of vaccination, and greater risk of trauma, including fights and traffic accidents9,23,24. Furthermore, cats were more likely to be affected than dogs, which may reflect species-specific susceptibilities as well as differences in management and adaptability to shelter conditions25,26.

Parasitic diseases were analyzed separately from other infectious conditions. Although parasitoses are infectious in nature, their high prevalence and distinct epidemiological and clinical implications within the rescued population justified their independent categorization, enabling a clearer assessment of their specific impact.

Diseases in felines

FIV infection was more prevalent in male and adult cats, a finding that supports the data from Burling et al.26, in a study conducted in the United States and Canada with 62,301 felines. This pattern may be attributed to the territorial and aggressive behavior of males, which facilitates viral transmission through bites during disputes.

Regarding Feline Respiratory Complex (FRC), the data from the present study differ from those reported by Rodrigues22,27 and Matos28, which indicate a higher prevalence in males. However, Burns et al.29 found no significant difference between sexes, a conclusion that aligns with Gaskell et al.30, who stated that there is no sex predisposition to the disease. Additionally, cats with owners showed a higher frequency of FRC compared to strays, possibly due to contact with animals previously exposed to pathogens, as well as the stress inherent to life in shelters.

In cases of ectoparasites, such as infestations by mites, fleas, lice, and ticks, no significant difference between sexes was observed, a result consistent with Mendes-de-Almeida et al.31, who analyzed the occurrence of these parasites in 292 urban cats in Rio de Janeiro. However, adult cats were more affected, which may be related to environmental factors and deficiencies in the immune system.

Regarding endoparasites in cats, the findings differ from those of Ramos et al.32, who did not identify a sex predilection for parasitic infection in shelter cats in Rio de Janeiro. However, it is emphasized that regular exams and updates to deworming protocols are crucial, especially in stray populations and shelters, where reinfection occurs frequently.

Otitis in cats showed a pattern similar to that described by Batista et al.33, who found a similar prevalence of the disease in a study conducted in Fortaleza with 60 cats, attributing crowding as a relevant factor for infestation34.

Traumatic wounds in cats were more common in male adult cats, possibly due to territorial and competitive behavior, making them more susceptible to physical confrontations. While many of these injuries result from fights, the possibility of injuries caused by intentional aggression, including physical violence and trauma caused by firearms or sharp objects, must be considered34. Studies indicate that approximately 9% of cats with these injuries are victims of abuse35,36,37,38.

Studies show a strong relationship between the Feline Gingivitis-Stomatitis Complex and viral infections, which may explain the moderate frequency of the disease in this article39. Feline Calicivirus (FCV) is one of the main agents involved, causing respiratory and ulcerative infections in the oral cavity and triggering an exacerbated immune-mediated response in susceptible cats40.

Furthermore, feline herpesvirus type 1 (FHV-1) and feline leukemia virus (FeLV) are frequently detected in affected animals, suggesting that these pathogens contribute to immunosuppression and the maintenance of the inflammatory process39. Coinfection with feline immunodeficiency virus (FIV) further exacerbates the disease, as it compromises cellular immunity, increasing susceptibility to secondary infections40.

Diseases in dogs

In dogs with owners, the analysis of disease origin reveals that, despite the presence of owners, there is a significant incidence of chronic and degenerative diseases, including neoplasms and inflammatory processes, as well as traumas possibly related to the environment and lifestyle of these animals.

In this study, puppies showed greater vulnerability to ectoparasite infestations, making them susceptible to infections and diseases transmitted by these vectors. Additionally, factors such as high population density, inadequate hygiene, and greater contact with contaminated environments favor the spread of these parasites41,42.

As in cats, the high incidence of traumatic wounds in dogs may be related to acts of abuse, considering that this species is frequently more affected than felines. According to Brandão38, 59.8% of victimized dogs suffer from this type of practice.

Otitis in dogs, due to its multifactorial etiology, may be associated with both genetic and environmental factors. Elements such as high population density, direct contact between healthy and sick animals, excessive moisture in pens, and the spread of pathogens through fomites, such as staff boots and aprons, are conditions that favor its occurrence43.

The findings on canine endoparasitoses are consistent with the results of Mariani et al.44, suggesting that adult dogs subjected to abandonment face high levels of stress, which may lead to immunosuppression and consequently a greater susceptibility to infections. Additionally, the immunological immaturity in younger animals may contribute to the high incidence of endoparasitic infections in this age group44,45.

The predominance of ehrlichiosis in adult and senior dogs may indicate a cumulative effect of exposure to the vector throughout life, as well as possible immunological alterations that increase the susceptibility of these animals with aging46.

Among the moderately frequent diseases, four stand out, all of dermatological origin: fungal dermatitis, atopic dermatitis, pyoderma, and neoplasia, highlighting the high prevalence of these conditions in shelter dogs. This pattern may be associated with adverse environmental conditions, stress-induced immunosuppression, and overcrowding of animals, which favors the spread of pathogens. These findings corroborate the results of Souza et al.34, who analyzed the prevalence of dermatological conditions in shelter dogs in the municipality of Belém-PA.

Finally, the high occurrence of TVT, periodontal disease, and fractures in adult and senior dogs suggests a cumulative impact of exposure to predisposing factors throughout life, such as inadequate diet, poor hygiene, higher trauma risk, and a predisposition to tumor development in senescence 47,48,49,50.

Conclusions

The epidemiological analysis of dogs and cats sheltered by the Integra Animal Project revealed a predominance of infectious and parasitic diseases, particularly among stray animals, likely associated with exposure to adverse environments, malnutrition, and trauma. In cats, the most frequent diagnoses were FIV and FRC, whereas in dogs, ehrlichiosis and parasitic conditions were more common.

Age-related patterns were also observed: while puppies and kittens generally showed better overall health conditions, seniors exhibited higher frequencies of chronic and infectious diseases, suggesting an effect of cumulative exposure and immunosenescence. Furthermore, dermatological conditions, especially ectoparasite infestations and skin infections, were common across both species, underscoring the influence of environmental and management factors in shelter settings.

These findings provide valuable insights into the health challenges faced by rescued animals in disaster scenarios. However, as this is an observational study, the associations identified cannot be interpreted as causal. The results highlight the importance of preventive measures such as vaccination, ectoparasite control, and sanitary management, as well as the development of specific strategies for the rescue and care of animals in environmental disaster contexts.