Using the SCT method, Echinococcus species were identified as E. granulosus s.l. and E. multilocularis based on specific morphological characteristics (Fig. 1). The gray wolf was heavily infected with E. granulosus s.l. and E. multilocularis (62,720 and 49,280 parasites, respectively). DNA of adult worms was analyzed by genus/species specific PCRs, and the worms were confirmed to be E. granulosus s.s. (G1) and E. multilocularis by COI and 12S rRNA gene sequence analysis, respectively. This study reports the co-infection of E. granulosus s.s. (G1) and E. multilocularis in a gray wolf in Erzurum province, which is a highly endemic area for both human CE and AE.
Previous reports on wolves showed that the prevalence rate of E. granulosus s.l. was 15% in Italy [17], 15% in Spain [18], 1.5% in Portugal [19], 7.6% in Poland [8], 3.8% in Estonia [20], 4.2% in Mongolia [9], 1% in Iran [21], 27% in Canada [10], and 62.6% in the USA [22]. The prevalence of E. multilocularis was 1.3% in France [23], 9.7–35.5% in Slovakia [7], 5.9% in Latvia [24], 3.4% in Mongolia [9], 1% in Iran [21], and 13% in Canada [10]. One case of echinococcosis in gray wolves has been reported in Turkey [11].
Human CE is present throughout Turkey, but it remains a significant public health concern, particularly in the rural areas of the eastern region [1]. The presence of E. granulosus s.l. in dogs was determined in Erzurum and the species were reported as E. granulosus s.s. (G1/G3), E. equinus (G4), E. ortleppi (G5), and E. canadensis (G6/G7) [25]. There was only one report of Echinococcus spp. in gray wolves in Turkey, which presented E. equinus and E. canadensis [11]. This study presents E. granulosus s.s. (G1) infection in a gray wolf in Turkey. Among the E. granulosus s.l. species, E. granulosus s.s. has a wildlife cycle that can directly interact with domestic contamination [26]. The overlap of domestic and wildlife cycles of E. granulosus s.s. was demonstrated in this study. This finding indicates a significant risk for human CE in this region.
Turkey is an endemic region for human AE, with approximately 100 new cases reported each year [5]. AE is a major public health concern in the country, particularly prevalent in rural areas located in the eastern regions [27]. There are available data on the presence and prevalence of E. multilocularis in the final hosts of Erzurum province: 10.5–42% in foxes [28], 3.6–8.3% in dogs [25, 29] and in a lynx [30] were presented. In addition, E. multilocularis was detected in stray dogs (8.7%) in a regional study covering the entire northeastern region of Turkey [29]. In this study, E. multilocularis was identified for the first time in a gray wolf in Turkey. The location of the infected wolf is close to the urban area of this province and this finding is of great public health significance.
Recently, wildlife has been increasingly recognized as a potential carrier of pathogens that can affect both domestic animals and humans. The growth in urbanization causes the transmission of zoonoses to humans through increased association of humans with synanthropic and wild animals. Echinococcus multilocularis typically persists in the wild cycle, but the change in the ecological environment and the behavior of red foxes, which are the main definitive hosts, cause transmission of this parasite into urban life [31, 32]. The urbanization of AE has already been explained by Deplazes et al. (2004) [31] in endemic regions for E. multilocularis in Europe. In Erzurum, E. multilocularis infection in foxes was found to be more common in urban areas than in rural areas [28]. Foxes are responsible for the majority of environmental contamination with E. multilocularis eggs, and other carnivores such as stray dogs and wolves may be affected by this contamination in both wild and domestic areas [2]. With previous reports of E. multilocularis in foxes and dogs, the infection of the gray wolf in this study may explain the reason for the high number of human AE cases in this region. Wolves have adapted to various terrestrial habitats and can also inhabit areas near human settlements. However, they generally avoid humans and prefer to establish their home ranges away from human-made structures [12, 33]. The wolf in this study was found close to the province, which may be related to habitat fragmentation and the need for anthropogenic food resources with adaptation to synanthropic life.
Intestinal analysis can estimate infection intensity [31], indicating the degree of parasite egg contamination in the environment and the continuity of the parasite's biological cycle [2]. In this study, gray wolf was found to be infected with both E. multilocularis and E. granulosus s.s. with high worm burdens, averaging 49,280 and 62,720 parasites, respectively. Compared to some other studies [8, 11, 34, 35] on wolves infected with E. granulosus s.l., a higher intensity was obtained in this study. In addition, E. multilocularis also had a high intensity in the wolf, similar to red foxes in Erzurum province [28]. These results indicate a high probability of environmental contamination with Echinococcus worms in the study area, which was also explained by previous studies [5, 6]. The adaptation of wild carnivores with high parasite loads to urban areas to access human food suggests an increased risk of AE in urban environments.
The sequence of E. granulosus s.s. (G1) (accession number OK357541) from this study showed 100% identity with those of E. granulsos s.s. from Iran (MN478490, OP185238 and OM663710), Palestine (KC109647), India (JX854029), Brazil (KT438848) and Turkey (MN990735, MN732821, MW421902, HM598451, MG886838). The acquired sequence for E. multilocularis (accession number: MT321279) demonstrated 100% identity with the sequences obtained from E. multilocularis in Poland (KF171966), Austria (MN444822), and Slovakia (MN444819).UK (JN175268), Germany (EU043372, L49455) and Turkey (MN820620, ON840214, MG818156, KX664085). The study found that the G1 genotype of E. granulosus s.s. was the most prevalent among adult parasites.