Current Distribution of Selected Vector‐borne Diseases in Domestic Dogs From Bucharest, Romania

ABSTRACT

Background

Canine vector‐borne diseases (CVBDs) include various illnesses affecting dogs. The purpose of this study was to investigate the prevalence of major CVBDs in domestic dogs in Bucharest, Romania's largest urban centre, which is situated along the Dâmbovița River in the southeastern region.

Material and methods

The present study included 317 dogs presented to a veterinary hospital for routine health examinations or specialised consultations between August 2020 and August 2024. Two rapid serological tests (SNAP 4Dx Plus and SNAP Leishmania) were used to assess infection rates.

Results

The findings revealed an overall seroprevalence of 8.8% for CVBDs, with Dirofilaria immitis exhibiting a prevalence of 12.62%. The seroprevalence of Ehrlichia spp. fluctuated over the years, peaking at 8.33% in 2022, resulting in an overall prevalence of 4.73%. An increase in Ehrlichia spp. seroprevalence during the 4 years was correlated with the presence of Rhipicephalus species in the region. Anaplasma spp. also showed a rising trend, with an overall prevalence of 4.42% and an increase from 2.94% in 2020 to 8.33% in 2024. In contrast, Borrelia burgdorferi exhibited low seroprevalence, and no positive cases for Leishmania spp. were detected.

Conclusion

This study assesses Bucharest's status as an endemic area for ehrlichial diseases and dirofilariosis, highlighting significant public health concerns. Globalisation, tourism and climate change are factors that influence vector biology, and it is crucial to develop a strategic management plan for the prevention and control of vector‐borne diseases.

Serological testing of 317 dogs in Bucharest (2020‐2024) revealed an overall Canine vector‐borne diseases (CVBD) seroprevalence of 8.8%, with Dirofilaria immitis (12.62%) being the most common. Shelter and older dogs had higher infection rates. Climate change and vector expansion may influence pathogen spread, underscoring the need for enhanced surveillance and preventive measures.

1. Introduction

Canine vector‐borne diseases (CVBD) include a wide variety of illnesses caused by bacteria, viruses, and eukaryotic parasites, transmitted primarily through arthropod vectors such as ticks, mosquitoes, and sandflies (Otranto et al. 2009a). The study of CVBD has gained importance due to current climate changes, increased human mobility, and the zoonotic risks associated with these diseases (e.g., dirofilariasis, leishmaniosis, ehrlichiosis and anaplasmosis) (Beugnet and Chalvet‐Monfray 2013; Beermann et al. 2023; Mateus et al. 2023). Several infectious pathogens transmitted by vectors, including Borrelia burgdorferi sensu lato complex, Anaplasma phagocytophilum, A. platys, Ehrlichia canis, E. ewingii, Leishmania infantum, Dirofilaria immitis, and D. repens, are known to infect both dogs and humans (Otranto et al. 2009b). In endemic regions, dogs serve as key hosts for parasites like Leishmania infantum and Dirofilaria spp. (Mendoza‐Roldan et al. 2020).

In Europe, numerous studies have investigated the distribution of CVBD and the seropositivity of dogs to various infectious agents, demonstrating that climate change, increased travel with dogs, and the rise in dog imports have influenced the spread of these diseases over the past decades (Wright et al. 2020; Bajer et al. 2023; Mateus et al. 2023). This has made the spread of CVBD a growing concern across continental Europe, particularly in Eastern and Northern regions.

Major serological studies on CVBD distribution in Europe have identified Romania in Southeastern Europe as having notably high positivity rates for D. immitis and Ehrlichia spp. (Mircean et al. 2012; Matei et al., 2021). Romania's rich biodiversity, with over 25 tick species (Estrada‐Peña et al. 2017), increases the likelihood of a significant rise in CVBD cases. Research also indicates that some areas of Romania, with its diverse arthropod species and warm climate, are endemic for heartworm disease, raising risks for both dogs and humans (Ciucă et al. 2018).

Dirofilaria immitis (heartworm) infections in Romania are well‐known, mainly in warmer regions like Bucharest (Ciucă et al. 2018; Mircean et al. 2012). The prevalence of D. immitis in dogs has been associated with environmental shifts, the introduction of invasive mosquito species (Fălcuţă et al. 2020), and the growing number of imported and stray dogs. Ehrlichia spp., a gram‐negative bacterium primarily transmitted by Rhipicephalus sanguineus, has also been detected in Romania, with local prevalences ranging from 2.1% to 11.1% (Mircean et al. 2012).

Anaplasma spp., a Gram‐negative bacterium transmitted by Ixodidae ticks, was reported in Romania with a seroprevalence rate of 5.99% (Miró et al. 2022). Additionally, other pathogens such as Borrelia burgdorferi and Leishmania infantum showed seroprevalence rates of 0.6% (13,995; 0.5–0.8%) for B. burgdorferi and for Leishmania spp. 0.6% (2546; 0.3–1.0%) (Cazan et al. 2020; Miró et al. 2022).

More than a decade ago, in Bucharest, the capital of Romania, a major tourist destination and key business hub in Southeastern Europe, dogs were seropositive for important CVBD (D. immitis, A. phagocytophilum, E. canis) (Ionita et al. 2013). No studies have been conducted since 2012 to assess the current situation.

This study aimed to investigate the infection by major CVBD in domestic dogs from Bucharest, using two rapid serological tests (SNAP 4Dx Plus and SNAP Leishmania) and to determine the risk factors related to the infection.

2. Materials and Methods

2.1. Study Area

Bucharest is the largest urban centre in Romania, located on the banks of the Dâmbovița River in the southeastern part of the country. With an official population of 1.76 million and a metropolitan area housing 2.3 million people, it ranks as the 8th most populous city in the European Union. The city spans an area of 240 km² and is divided into six districts, while its metropolitan region covers 1,811 km². Bucharest is a beta global city, serving as a major cultural, political, and economic hub, as well as the seat of Romania's government (Ionac et al. 2020).

The Dâmbovița River flows through Bucharest before joining the Argeș River, a tributary of the Danube River. Several lakes, including Lake Herăstrău, Lake Floreasca, Lake Tei and Lake Colentina, are situated in the northern part of the city along the Colentina River, a tributary of the Dâmbovița. Additionally, Lake Cișmigiu, an artificial lake, is located in the heart of the city and is surrounded by the Cișmigiu Gardens (Stancu et al. 2017).

Bucharest experiences a humid continental climate or a humid subtropical climate, characterised by hot, humid summers and cold, snowy winters. Due to its location on the Romanian Plain, winters in the city can be windy, though urbanisation helps reduce some of the wind's impact (Cheval et al. 2022).

2.2. Sample Collection

Between August 2020 and August 2024, blood samples were collected from 317 dogs in Bucharest, Romania. The dogs were presented to a referral veterinary hospital for various medical reasons, including general health checks, cardiology consultations, and surgery evaluations. Only dogs over 12 months old were included in the study, with informed consent obtained from their owners. The risk of VBD and the aim of the study were explained to each owner, and they were asked to sign a written informed consent and give their approval for the use of data.

Each dog underwent a clinical assessment, and individual characteristics and previous external antiparasitic treatments were recorded. Diagnostic blood samples were drawn from the cephalic or jugular vein and stored in paired serum and EDTA tubes.

2.3. Sample Examination

Serum samples were tested for antibodies against Leishmania spp. using SNAP Leishmania, and for Anaplasma spp., Ehrlichia spp., and B. burgdorferi s.l., as well as for Dirofilaria immitis antigen, using a commercial rapid ELISA test (SNAP 4Dx Plus). For screening for CVBD, the SNAP 4Dx Plus test (IDEXX Laboratories, Westbrook, ME) is a rapid in‐house ELISA designed for the simultaneous detection of antibodies to Anaplasma phagocytophilum, A. platys, Ehrlichia canis, E. ewingii, Borrelia burgdorferi, and heartworm antigen.

Data related to the age (in years), breed, and service of the dogs were collected and incorporated into an Excel database.

2.4. Statistical Analyses

Statistical analyses were performed using EpiInfo7 software (CDC, USA). The prevalence and 95% confidence intervals (CI) were calculated for each pathogen, both globally and according to specific categories. Differences between categories were assessed using a chi‐square test and considered statistically significant at a p‐value < 0.05.

3. Results

A total of 317 dogs were included in this study. Between 2020–2024, serological tests for vector‐borne diseases were performed on samples distributed as follows: 34 samples were collected in 2020, 33 in 2021, 60 in 2022, 94 in 2023 and 96 in 2024 (Table 1). Among the 317 dogs included in the study, there was a notable gender distribution, with 174 (54.89%) males and 143 (45.11%) females. Regarding breed classification, 184 (58.05%) dogs were identified as purebred, while 133 (41.96%) were classified as mongrel. As for the service roles, a small part of the dog population served specific purposes: 5 (1.58%) were identified as blood donors, another 5 (1.58%) were employed as hunting dogs, and 7 (2.21%) originated from shelters in Bucharest. Additionally, 8 (2.52%) dogs were engaged in sports activities, another 8 (2.52%) served as tracking dogs, and 12 (3.79%) were utilised as therapy dogs. 272 (85.8%) dogs were household pets living in neighbourhoods throughout Bucharest.

TABLE 1.

Sample distribution according to years, sex, breed, age, category and antiparasitic status.

	Frequency	%	95% CI
Year
2020	34	10.73	7.78–14.61
2021	33	10.41	7.51–14.26
2022	60	18.93	15–23.6
2023	94	29.65	24.89–34.90
2024	96	30.28	25.49–35.55
Sex
M	174	54.89	49.39–60.28
F	143	45.11	39.72–50.61
Breed
Pure breed	184	58.04	52.55–63.35
Mongrel	133	41.96	36.65–47.45
Service
Blood donor	5	1.58	0.68–3.64
Hunting dog	5	1.58	0.68–3.64
Shelter dog	7	2.21	1.07–4.49
Sport dog	8	2.52	1.28–4.9
Tracking	8	2.52	1.28–4.9
Therapy dog	12	3.79	2.18–6.5
Pet	272	85.8	81.53–89.22
Age group
1–5 years	104	32.81	27.87–38.16
6–10 years	117	36.91	31.78–42.35
11–18 years	96	30.28	25.49–35.55
External antiparasitics used
Yes	186	58.68	53.18–63.96
No	131	41.32	36.04–46.82
Reason for presenting
Routine check‐up	262	82.65	78.1–86.42
Specialist consult/intervention	55	17.35	13.58–21.9
TOTAL	317	100	—

The dogs were organised into three distinct age groups: 104 (32.81%) dogs fell into Group A (aged 1–5 years), 117 (36.91%) into Group B (aged 6–10 years), and 96 (30.28%) into Group C (ages 11–18 years). Many owners administered acaricidal treatment, with 186 (58.68%) dogs received veterinary care, including prophylactic acaricidal treatments. Conversely, 131 (41.32%) dogs had no recent treatment history. From a medical care perspective, 262 (82.65%) dogs were presented for routine health checks. In contrast, 55 (17.35%) dogs were brought in for specialist consultations. The annual prevalence of infectious agents can be assessed in Table 2.

TABLE 2.

Annual prevalence (%) and 95% CI for individual pathogens.

Year	Ehrlichia spp.	Anaplasma spp.	Borelia burgdoferi	Dirofilaria immitis
Positive % of tests (95% CI)
2020	2.94% (0.07–15.33%)	2.94% (0.07–15.33%)	0% (0–10.28%)	8.82% (1.86–23.68%)
2021	3.03% (0.08–15.76%)	3.03% (0.08–15.76%)	0% (0–10.58%)	21.21% (8.98–38.91%)
2022	8.33% (2.76–18.39%)	0% (0–5.96%)	1.67% (0.04–8.94%)	13.33% (5.94–24.59%)
2023	2.13% (0.26–7.48%)	4.26% (1.17–10.54%)	0% (0–3.85%)	15.96% (9.22–24.95%)
2024	6.25% (2.33–13.11%)	8.33% (3.67–15.76%)	0% (0–3.77%)	7.29% (2.98–14.45%)
TOTAL	4.73% (2.89–7.66%)	4.42% (2.65–7.28%)	0.32% (0.06–1.76%)	12.62% (9.4–16.73%)

The seroprevalence of Ehrlichia spp. fluctuated over the years, peaking notably at 8.33% in 2022, without significant year‐to‐year variations (χ 2 = 4,08; df = 4; P = 0.39).

(Table 3) Shelter dogs showed a noticeably higher seroprevalence (28.57%), though this difference was not statistically significant (χ² = 10.71; df = 6; P = 0.09). No significant variations were found across breed, sex, or age categories. However, the use of prophylactic treatments revealed some visible differences, which also did not reach statistical significance (χ² = 3.14; df = 1; P = 0.06).

TABLE 3.

Seroprevalence of Ehrlichia spp. according to categorical variables.

	Frequency	%	95% CI	χ2; df; p
Year
2020	1	2.94	0.07–15.33	4.08; 4; 0.39
2021	1	3.03	0.08–15.76
2022	5	8.33	2.76–18.39
2023	2	2.13	0.26–7.48
2024	6	6.25	2.33–13.11
Sex
M	8	4.6	2.01–8.86	0; 1; 1
F	7	4.9	1.99–9.83
Breed
Pure breed	8	4.35	1.9–8.39	0.01; 1; 0.79
Mongrel	7	5.26	2.14–10.54
Service
Blood donor	0	0	0–52.18	10.71; 6; 0.09
Hunting dog	0	0	0–52.18
Shelter dog	2	28.57	3.67–70.96
Sport dog	0	0	0–36.94
Tracking	0	0	0–36.94
Therapy dog	0	0	0–26.46
Pet	13	4.78	2.57–8.03
Age group
1–5 years	6	5.77	2.15–12.13	4.01; 2; 0.13
6–10 years	2	1.71	0.21–6.04
11–18 years	7	7.29	2.98–14.45
External antiparasitics used
Yes	5	2.69	0.88–6.16	3.14; 1; 0.06
No	10	7.63	3.72–13.59
Reason for presenting
Routine check‐up	14	5.34	2.95–8.8	0.59; 1; 0.48
Specialist consult/intervention	1	1.82	0.05–9.72
TOTAL	15	4.73	2.89–7.66	—

Most dogs testing positive for Ehrlichia spp. were seen during routine check‐ups. The overall seroprevalence across all categories was 4.73% (2.89–7.66, 95% Cl).

The seroprevalence of Anaplasma spp. in the studied dog population shows significant variability over the years (Table 4). In 2020, the prevalence was 2.94%, which slightly increased to 3.03% in 2021. However, there were no reported cases in 2022. The prevalence rose again to 4.26% in 2023 and reached 8.33% in 2024. Although it seems that there is an increasing trend across the years, the data are not statistically significant, potentially due to wide confidence intervals (χ² = 6.59; df = 4; P = 0.16). Females (5.59%) showed a higher prevalence when compared to males (3.45%), but without statistical significance (χ² = 4.23; df = 1; P = 0.41).

TABLE 4.

Seroprevalence of Anaplasma spp. according to categorical variables. Significant statistical differences are marked with “*”.

	Frequency	%	95% CI	χ2; df; p
Year
2020	1	2.94	0.07–15.33	6.59; 4; 0.16
2021	1	3.03	0.08–15.76
2022	0	0	0–5.96
2023	4	4.26	1.17–10.54
2024	8	8.33	3.67–15.76
Sex
M	6	3.45	1.28–7.35	4.23; 1; 0.41
F	8	5.59	2.45–10.73
Breed
Pure breed	7	3.8	1.54–7.68	0.12; 1; 0.58
Mongrel	7	5.26	2.14–10.54
Service
Blood donor	0	0	0–52.18	12.38; 6; 0.05
Hunting dog	0	0	0–52.18
Shelter dog	2	28.57	3.67–70.97
Sport dog	1	12.5	0.32–52.65
Tracking	0	0	0–36.94
Therapy dog	0	0	0–26.46
Pet	11	4.04	2.04–7.12
Age group
1–5 years	1	0.96	0.02–5.24	4.7; 2; 0.09
6–10 years	8	6.84	3–13.03
11–18 years	5	5.21	1.71–11.74
External antiparasitics used
Yes	4	2.15	0.59–5.41	4.25; 1; 0.02*
No	10	7.63	3.72–13.59
Reason for presenting
Routine check‐up	12	4.58	2.39–7.86	0; 1; 1
Specialist consult/intervention	2	3.64	0.44–12.53
TOTAL	14	4.42	2.65–7.28	—

Purebred and mongrel dogs showed similar prevalence rates. Service roles indicated that blood donors and hunting dogs had no positive cases, whereas shelter dogs (28.57%) exhibited a high seroprevalence (χ² = 12.38; df = 6; P = 0.05).

The age group analysis showed that dogs aged 6–10 years had the highest prevalence; however, this was not statistically significant (χ² = 4.7; df = 2; P = 0.09)

Dogs that were not treated with external antiparasitics exhibited a higher prevalence of Anaplasma spp. compared to those who underwent prophylactic treatments (χ² = 4.25; df = 1; P = 0.02).

Most dogs were presented for routine health checks, suggesting that regular veterinary visits can facilitate early detection of infections. The overall seroprevalence of Anaplasma spp. stood at 4.42%.

The seroprevalence of B. burgdorferi s.l. in the studied dog population indicates a very low incidence of infection, with a single case identified in 2022, resulting in an overall prevalence of only 0.32%.

The seroprevalence of D. immitis in dogs displayed significant fluctuations throughout the study period, with an overall prevalence of 12.62% between 2020 and 2024 (Table 5). The year 2021 showed the highest seroprevalence at 21.21%. This was followed by 15.96% in 2023, while 2024 saw a decrease to 7.29%. No statistically significant differences in prevalence were observed between males (13.22%) and females (11.89%) (χ² = 0.03; df = 1; P = 0.73).

TABLE 5.

Seroprevalence of Dirofilaria immitis according to categorical variables. Significant statistical differences are marked with “*”.

	Frequency	%	95% CI	χ2; df; p
Year
2020	3	8.82	1.86–23.68	6.1; 4; 0.19
2021	7	21.21	8.98–38.91
2022	8	13.33	5.94–24.59
2023	15	15.96	9.22–24.95
2024	7	7.29	2.98–14.45
Sex
M	23	13.22	8.57–19.17	0.03; 1; 0.73
F	17	11.89	7.08–18.35
Breed
Pure breed	15	8.15	4.63–13.09	6.99; 1; 0.005*
Mongrel	25	18.8	12.55–26.48
Service
Blood donor	0	0	0–52.18	4.5; 6; 0.6
Hunting dog	0	0	0–52.18
Shelter dog	2	28.57	3.67–70.97
Sport dog	1	12.5	0.32–52.65
Tracking	0	0	0–36.94
Therapy dog	1	8.33	0.21–38.48
Pet	36	13.24	9.44–17.85
Age group
1–5 years	8	7.69	3.38–14.6	4.54; 2; 0.1
6–10 years	15	12.82	7.36–20.26
11–18 years	17	17.71	10.67–26.83
External antiparasitics used
Yes	9	4.84	2.24–8.99	23.02; 1; <0.0001*
No	31	23.66	16.68–31.88
Reason for presenting
Routine check‐up	33	12.6	8.83–17.23	0; 1; 1
Specialist consult/intervention	7	12.73	5.27–24.48
TOTAL	40	12.62	9.4–16.73	—

A notable difference in prevalence of D. immitis was found between pure breeds and mongrel dogs (χ² = 6.99; df = 1; P = 0.005).

No differences in prevalences were evident across service types; however, there was a higher probability of exposure to D. immitis among shelter dogs (28.57%) when compared with pet dogs (13.24%) (χ² = 4.5; df = 6; p = 0.06).

Age analysis showed that dogs aged 11–18 years (Group C) exhibited the highest prevalence of exposure to D. immitis, though this was not statistically significant (χ² = 4.54; df = 2; P = 0.1). Significant statistical differences (χ² = 23.02; df = 1; p < 0.0011) were noted when comparing dogs that received external antiparasitics with those that did not receive any preventive treatment.

None of the dogs included in the present study were positive for Leishmania infantum.

Regarding co‐infections, only two (0.63%) dogs presented a positive result for two infectious agents: one was positive for D. immitis antigen and Ehrlichia spp. antibody, and one was positive for Anaplasma spp. antibody and Ehrlichia spp. antibody.

4. Discussion

In this study, point‐of‐care ELISA testing was used to assess the prevalence of CVBDs across Bucharest. The results showed an overall seroprevalence of 8.8% for CVBDs, including a 12.62% prevalence of D. immitis. Various mosquito species, such as Culex spp., Aedes spp., and Anopheles spp., were identified as potential vectors in southeastern Romania and Bucharest (Stancu et al., 2022). A related European study by Miró et al. (2022) found a similar seroprevalence of D. immitis (11.5%) in Romania, aligning with the findings of this research. A study examining the prevalence and distribution of Dirofilaria spp. and Acanthocheilonema reconditum infections in Romanian dogs found that D. immitis was predominantly located in the southern part of the country, near major rivers (Ionică et al. 2015). This makes Bucharest, a city situated along the Dâmbovița River and home to several lakes, an ideal environment for mosquito vectors and transmission of the nematode. Mongrel dogs exhibited a higher prevalence of D. immitis infection (18.8%) compared to purebred dogs (8.15%), which was not surprising as it is possible they were coming from shelters, where dogs tend to spend more time outside, where they may be more exposed to mosquito bites (Napoli et al. 2023). Additionally, the infection was more common in dogs from shelters, with a prevalence of 28.57%. This could be explained either by the lack of prophylactic treatments administered to shelter dogs or due to their housing conditions as well as the presence of different water sources in the environment that favour the mosquitoes' life cycle (Fălcuţă et al. 2020). Age also played a significant role, as older dogs (Group C) had a prevalence of 17.71%, while younger dogs (Group A) showed a lower prevalence of 7.69%. Adult and older dogs are known to be more commonly infected, as they were more exposed to vector activity during their lifetime (Ciucă et al. 2023). These findings may be linked to insufficient or absent repellent or anti‐biting treatment and prolonged exposure to the parasites, which could increase the likelihood of infection. From a One Health perspective, Bucharest is identified as an endemic area for D. immitis (Ciucă et al. 2016). It is crucial to note that dirofilariasis is a zoonotic disease, with an increasing number of reports of human pulmonary dirofilariasis in recent years (Ciucă et al., 2018; Department of Radiology and Medical Imaging, University of Medicine and Pharmacy of Craiova, Romania et al., 2023; Morosanu et al., 2024). In a seroepidemiological survey conducted in Romania and Moldova, the results focusing on Bucharest revealed a seroprevalence of 18.2% for D. immitis exposure among humans (Ciucă et al., 2018). A potential explanation for the peak of dirofilariasis in 2021 observed in this study could be linked to the recent introduction of Aedes albopictus in Romania, known as an important vector for Dirofilaria spp. (Fălcuţă et al. 2020). However, a significant decrease was noted in 2024, which may be attributed to effective mosquito bite prevention, increased public awareness, and the successful implementation of preventive strategies as people became more aware.

The overall exposure to Ehrlichia spp. in Bucharest was found to be 4.73%. The study by Miró et al. (2022) showed a prevalence of 7% in Romania. A similar percentage (7.29%) was noted in dogs from Group C (aged 11–18 years), which were primarily from shelters and lacked tick prevention treatment. This highlights the need for enhanced education for both veterinarians and dog owners regarding preventive measures and the associated risks from a One Health perspective. In Romania, the first reported indigenous clinical case of canine ehrlichiosis was documented by Morar et al. (2015), while previous studies have shown a prevalence ranging between 2.1% and 11.1% (Mircean et al. 2012; Miró et al. 2022). To the author's knowledge, there were no documented cases of canine ehrlichiosis in the Bucharest area or southeastern Romania, only seroepidemiological surveys (Mircean et al. 2012). It is important to note that cross‐reactivity has been identified using SNAP tests between Ehrlichia species and Anaplasma species (Facile et al. 2024). The rise in Anaplasma spp. prevalences from 2020 to 2024 may be linked to potential changes in the life cycle of R. sanguineus. This remains a hypothesis, especially given the high prevalence of Ehrlichia spp. in 2024. Further studies are needed to confirm any changes in tick biology and distribution in response to climate change. Possible explanations for the detection of ehrlichial exposure may include changes in tick biology attributed to climate change, resulting in warmer and more humid winters (Gilbert 2021). Another potential explanation could be the acquired resistance to certain acaricide treatments (Jongejan et al. 2024). The SNAP test showed significantly higher sensitivity (84.7% for A. phagocytophilum and 83.1% for A. platys) compared to other point‐of‐care tests (39.0% for A. phagocytophilum and 57.6% for A. platys). Additionally, the specificity of the SNAP test (95.8% for A. phagocytophilum and 99.2% for A. platys) was substantially greater than that of alternative tests (85.6% for A. phagocytophilum and 82.5% for A. platys). A comparison of the first‐ and second‐generation SNAP 4Dx Plus tests revealed that the second‐generation test enhanced serological detection of Anaplasma spp. and Ehrlichia spp. in naturally infected dogs (Richardson et al. 2023). The SNAP 4Dx Plus tests were used to conduct the survey; however, cross‐reactivity cannot be entirely ruled out.

Romania appears to have a higher seroprevalence of Ehrlichia spp. compared to neighbouring countries, such as Hungary, which reports a prevalence of 0.2% (Miró, 2022), while it is lower than Serbia, where the prevalence is 11.06%. The differences in seroprevalence compared to Hungary may be attributed to effective stray dog management, local health prevention policies, and the regular use of acaricides, biological control agents, and tick repellents. The seroprevalence observed in Bucharest might also be influenced by climate and the city's geographic location, underscoring the necessity for effective integrated prevention strategies (Mihai et al., 2022). Additionally, an important aspect of epidemiology is the role of dogs as reservoirs of infection, emphasising the need for effective strategies to prevent the spread of diseases (Hamel et al. 2012).

In comparison to other studies (Miró et al. 2022), the seroprevalence of Anaplasma spp. was lower, recorded at only 4.42% of dogs. Overall, the seroprevalence across Romania is reported to be 5.99% (Miró et al. 2022). The affected dogs were primarily those without preventive treatment, as well as adult and older dogs from shelters or those serving as hunting dogs. It is important to note that some discrepancies may exist, as the hunting areas are located outside the city limits.

None of the dogs in the present study tested positive for L. infantum, although competent sandflies have been identified in South‐Eastern Romania (Cazan et al., 2021), and positive DNA samples were detected in a dog kennel in Arges County (Cazan et al., 2020). One single clinical case of autochthonous canine leishmaniosis (CanL) was reported in Romania during the past decade, originating from Vâlcea County (Mircean et al. 2014).

Only one dog tested positive for antibodies against B. burgdorferi, yielding a seroprevalence consistent with findings from other studies (Miró et al. 2022), suggesting that the disease is rare in Bucharest and Romania. The primary vector for B. burgdorferi is Ixodes ricinus. However, in southeastern Romania, Rhipicephalus spp. appears to be the most prevalent vector (Ionita et al., 2016).

The changing epidemiology of arthropod‐borne diseases in Europe can be linked to several factors, such as climate change, globalisation, and shifts in land use. The rising temperatures caused by climate change have enabled the spread of various vector species across Europe (Beugnet and Chalvet‐Monfray 2013), including the significant geographical expansion of R. sanguineus, which is now endemic in the Balkans, Romania, and Bulgaria (Wall et al., 2013).

Additionally, alterations in vector life cycles and resistance to preventive treatments contribute to this issue. Consequently, there is an urgent need for improved surveillance measures and the development of new alert and control strategies to address the increasing risk of these diseases in domestic animals. It is also crucial to recognise the endemic nature of D. immitis in Bucharest and Romania, as it poses a risk for zoonotic diseases (Ciucă et al. 2018). Furthermore, the presence of Rhipicephalus spp. in Bucharest, in the context of climate change, should be considered when assessing the zoonotic risk for viral and rickettsial diseases. This is especially important for tourists from non‐endemic areas, as it raises the potential for disease transmission and poses a public health concern.

5. Contribution to the Field Statement

This study highlights that Bucharest is an endemic area for rickettsial diseases and dirofilariosis, raising important public health concerns. It is vital to acknowledge the significant variability of vectors, especially mosquitoes and Rhipicephalus species, which serve as primary disease transmitters that can impact both humans and their companion dogs. Given the influences of globalisation, tourism, and climate change, it is essential to establish a strategic management plan for the prevention and control of vector‐borne diseases. Further research is needed to evaluate current prevention strategies and their effectiveness, investigate potential drug resistance in vectors, and examine changes in their life cycles. This study provides an updated overview of canine vector‐borne diseases in the rapidly developing capital of Bucharest and highlights public health concerns.

Author Contributions

Ioana Sandu and Georgiana Deak designed the study and wrote the manuscript. Ioana Sandu and Cristian Daniel Cristea performed the fieldwork, collected the data, and performed the experiments. Angela M. Ionică performed the statistical analysis and revised the manuscript. All authors participated in the discussion of the results and were involved in correcting and approving the final manuscript.

Ethics Statement

The authors confirm that they have complied with the journal's ethical policies, as outlined in the author's guidelines. Furthermore, they declare that they adhered to the National Ethical Guidelines regarding Animal Welfare and Care.

Consent

Each owner provided written informed consent, which was signed to authorize the use of the specified data.

Conflicts of Interest

The authors declare no conflicts of interest.

Peer Review

The peer review history for this article is available at https://www.webofscience.com/api/gateway/wos/peer‐review/10.1002/vms3.70415.

Data Availability Statement

The data supporting the findings of this study can be obtained from the corresponding author(s), [IS, GD], upon reasonable request.