Intestinal echinococcosis in a dog from Missouri

Abstract

CASE DESCRIPTION A 17-week-old 14.4-kg (31.7-lb) female German Shepherd Dog from Missouri with a history of multiple intermittent episodes of vomiting and diarrhea underwent exploratory celiotomy. CLINICAL FINDINGS At the time of surgery, the dog was bright, alert, and responsive, with a tender abdomen and palpable mesenteric lymph nodes. Hematologic data revealed mild leukocytosis, mild hypoproteinemia, and mild hypoalbuminemia. Moderate petechiation of the jejunal serosa and prominent mesenteric lymph nodes, but no palpable obstructions, were found during surgery. Jejunal and lymph node biopsies were performed; histologic examination revealed multiple segments of adult cestodes up to 700 μm long in the jejunum. Segments had a scolex and contained approximately 30- to 35-μm-diameter ova, morphologically compatible with Echinococcus spp. Fecal flotation revealed numerous proglottids and ova similar to those recognized histologically. Results of PCR assays confirmed Echinococcus multilocularis of E4 haplotype (a European strain). TREATMENT AND OUTCOME Praziquantel (5 mg/kg [2.3 mg/lb], SC, once) was administered after surgery; treatments after hospital discharge included praziquantel (10 mg/kg [4.5 mg/lb], PO, once). No proglottids or ova were observed by fecal flotation after the treatments. The dog remained healthy without gastrointestinal signs 1 year later. CLINICAL RELEVANCE The dog of this report had no travel history outside the state of Missouri. To the authors’ knowledge, this is the first report of intestinal E multilocularis infection in a pet dog in the contiguous United States and first detection of a European strain of E multilocularis in this country. Findings suggested possible establishment of a European strain of this zoonotic pathogen in the contiguous United States.

Pathology in Practice

“…4 Also, a case of AE was reported recently in a dog in northern Virginia 3 and a case of intestinal E multilocularis infection was reported in Missouri. 9 Increased numbers of the reported cases of AE in dogs suggest that E multilocularis infection is on the rise both in North America and Europe. 2,6,10 Even though alveolar cysts in the abdomen of dogs are not zoonotic, it is important to keep in mind that the owner and the dog could have been exposed to a common source of infectious eggs in the environment.…”

Alveolar echinococcosis in a dog in Missouri, USA

“…7,8,11,16,21 We employed validated E. multilocularis species-specific primers. 15,21 The PCR products of cob, nad2, and cox1 were directly sequenced in both directions; nucleotide identities were calculated with SIAS (http://imed.med. ucm.es/Tools/sias.html), and the sequences were aligned (MEGA X v.10.2.6; https://www.megasoftware.net/).…”

“…[2][3][4] Although the main definitive hosts for E. multilocularis are wild canids (e.g., foxes and coyotes), dogs can also be definitive hosts. [2][3][4]15 Humans and dogs can become aberrant intermediate hosts and develop AE when eggs of E. multilocularis are ingested accidentally. Historically, 2 endemic regions of E. multilocularis were recognized within North America: the Northern Tundra Zone of Alaska and the Canadian Arctic, and the North Central Region (NCR), including 3 Canadian provinces (Alberta, Saskatchewan, Manitoba) and 13 U.S. states (Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Montana, Nebraska, North Dakota, Ohio, South Dakota, Wisconsin, Wyoming).…”

“…4 Central Indiana had been considered the southern limit; Ohio and Michigan had been considered the eastern limit for this parasite in the contiguous United States based on published data. 4,18,27 Evidence of endemicity of E. multilocularis in Missouri was based on unpublished data in foxes 24 until a report of the first confirmed case of intestinal echinococcosis (IE) in a juvenile pet dog in Missouri in 2020, 15 which was the first detection of a European strain (E4 haplotype) of E. multilocularis in a pet dog in the contiguous United States. 15 In addition, a canine AE case had been reported in an adult pet dog in Virginia.…”

“…4,18,27 Evidence of endemicity of E. multilocularis in Missouri was based on unpublished data in foxes 24 until a report of the first confirmed case of intestinal echinococcosis (IE) in a juvenile pet dog in Missouri in 2020, 15 which was the first detection of a European strain (E4 haplotype) of E. multilocularis in a pet dog in the contiguous United States. 15 In addition, a canine AE case had been reported in an adult pet dog in Virginia. 30 Molecular investigation with mitochondrial gene nad2 revealed that the E. multilocularis in the Virginia dog was consistent with European strains.…”