Fatal pulmonary cysticercosis caused by Cysticercus longicollis in a captive ring-tailed lemur (Lemur catta)

Comprehensive Diagnosis, Treatment, and Outcome of Taenia crassiceps Cysticercosis in a Ring-Tailed Lemur (Lemur catta) from a Croatian Zoo: No Longer Unusual?

Taenia crassiceps is a zoonotic tapeworm of the genus Taenia that is distributed throughout the Northern Hemisphere. Wild and domestic carnivores are final hosts, while rodents and rabbits are primarily intermediate hosts, although many other mammals may harbour the larval stage, Cysticercus longicollis. This case report aims to describe C. longicollis infection in a lemur and molecularly characterise the isolated parasite. The excised lesion was subjected to morphological and histopathological examination, which revealed cysticerci of the tapeworm. Formalin-fixed and paraffin-embedded block (FFPEB), as well as the cysticerci fixed with formalin stored for one year, were subjected to molecular analysis, which aimed at detecting the partial mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of Taenia sp. Based on the morphological characteristics, the parasite was identified as a metacestode of T. crassiceps. The presence of the cox1 gene was detected using polymerase chain reaction (PCR) in all samples. A randomly selected PCR product was sequenced and compared with other sequences from the GenBank database, confirming that the detected parasite was T. crassiceps. This article reports the first case of T. crassiceps cysticercosis in a lemur (Lemur catta) in Croatia and emphasises the potential risk of transmission from wild carnivores.

Case-report: Massive infection by Cysticercus longicollis in a captive Lemur catta from Italy

An adult male ring-tailed lemur (Lemur catta) from a biopark of northern Italy was submitted to necropsy. A multi-organ parasitic infection was macroscopically evident. Abundant sero-hemorrhagic fluid with larval parasites was present in all cavities. The microscopic evaluation of parasites and the molecular characterization revealed the presence of Cysticercus longicollis (the larval stage of Taenia crassiceps). Histology of liver, lungs, intestine and urinary bladder revealed several larval parasites surrounded by a severe lymphocytic infiltrate, fibrous tissue and hemorrhages. This is the first report of a ring-tailed lemur with an infection of C. longicollis in Italy. The source of infection is still not known however, the discovery of this parasite in a captive lemur poses more attention on the control of parasitic diseases implementing monitoring tests and biosecurity measures.

Subcutaneous Taenia crassiceps Cysticercosis in a Ring-Tailed Lemur (Lemur catta) in a Serbian Zoo

BACKGROUND

Different rodent species serve as natural intermediate hosts for carnivore tapeworm Taenia crassiceps. However, this cestode occasionally infects various dead-end hosts including humans and other primates and may cause serious pathological implications with potentially fatal outcome. In this paper, we present subcutaneous cysticercosis caused by T. crassiceps, found in a previously healthy 17-years-old male ring-tailed lemur (Lemur catta) in a Serbian Zoo.

CASE PRESENTATION

The animal was presented to a veterinarian with a history of periarticular subcutaneous swelling in medial right knee region. After fine needle aspiration revealed cycticerci-like structures, a surgery was performed for complete extraction of the incapsulated multicystic mass containing numerous cysticerci. Collected material was sent for parasitological, histological and molecular analysis. One month after surgery, the lemur died due to respiratory failure unrelated to cysticercosis. Based on morphological features of large and small hooks and characteristic proliferation of cysticerci, a metacestode of T. crassiceps was identified, which was confirmed after sequencing of obtained amplicons and comparing them to the GenBank database.

CONCLUSIONS

This is one of the few reported cases of T. crassiceps cysticercosis in a ring-tailed lemur, and the first one in Serbia. This endangered species seem to be more sensitive for T. crassiceps than other non-human primates, which represents serious conservation challenge for captive animals. Due to zoonotic nature of the parasite, challenging diagnosis, severity of the disease, difficult treatment and possible fatalities, high biosecurity measures are of particular importance, especially in endemic regions.

Molecular Confirmation of Taenia crassiceps Cysticercosis in a Captive Ring-Tailed Lemur (Lemur catta) in Poland

(1) Background: Taenia crassiceps is a cosmopolitan tapeworm endemic to the northern hemisphere with an indirect lifecycle. Its definitive hosts are carnivores, and its intermediate hosts are rodents and rabbits. Nonhuman primates in zoos appear to be highly susceptible to T. crassiceps cysticercosis. The aim of this study was to confirm the presence and the molecular characterization of T. crassiceps cysts isolated from a captive ring-tailed lemur. (2) Methods: Surgery revealed multifocal, transparent saccules containing several thin-walled tapeworm cysticerci. In some of the metacestodes, single or multiple exogenous buds from daughter cysticerci were spotted. A molecular analysis was performed to confirm our morphological examinations, using two protocols to obtain the partial nad1 and cox1 genes of the Taenia sp. (3) Results: On the basis of morphological features and molecular analysis, the cysticerci were identified as T. crassiceps metacestodes, and products taken from the PCRs were sequenced. With respect to interpreting the sequencing results of the obtained amplicons, we compared them with data in the GenBank database, proving that, in this case, the causative agent was indeed T. crassiceps. (4) Conclusions: The received data can be used to supplement descriptions of this species. To the best of our knowledge, this is the first case of cysticercosis caused by T. crassiceps in a nonhuman primate in Poland.

THORACIC RADIOGRAPHY AND TRANSTHORACIC ECHOCARDIOGRAPHY IN CLINICALLY HEALTHY RING-TAILED LEMURS (LEMUR CATTA)

Cardiac disease has been recognized as a major cause of death in captive nonhuman primates, which necessitates diagnostic (imaging) techniques to screen for and diagnose preclinical and clinical stages of possible cardiac conditions. Echocardiography is currently the most commonly used diagnostic tool for evaluation of cardiac anatomy and function. Complete with thoracic radiography and blood levels of two cardiac biomarkers, N-terminal probrain natriuretic peptide (NT-proBNP) and cardiac troponin T (cTnT), it gives an extensive examination of the cardiorespiratory system. The purpose of this cross-sectional cohort study is to describe normal thoracic anatomy using thoracic radiography, and to provide normal values for echocardiographic measurements in 20 ring-tailed lemurs (Lemur catta). Additionally, cardiac biomarkers were determined. Three radiographic projections of the thoracic cavity and a complete transthoracic echocardiography were performed in 20 clinically healthy ring-tailed lemurs during their annual health examinations. Similar standard right parasternal and left apical echocardiographic images were obtained as described in dogs and cats and normal values for routine two-dimensional (2D-), time-motion (M-) and Doppler mode measurements were generated. Furthermore, a noninvasive smartphone base ECG recording and blood concentrations of cardiac biomarkers were obtained. Other radiographic measurements are provided for the skeletal and respiratory systems such as the trachea to inlet ratio and tracheal inclination. Knowledge of the normal radiographic thoracic and echocardiographic anatomy and function are fundamental for the diagnosis and follow-up of cardiac disease in affected individuals and for species screening, and will be of added value in future research in and conservation of this endangered species.

Alveolar echinococcosis in a dog in the eastern United States

An 8-y-old Labrador Retriever was presented to a small animal practice in northern Virginia with a history of recent lethargy. Physical examination findings were unremarkable. Ultrasound revealed several large hepatic masses and multiple smaller masses involving the pancreas. Cytologic findings on fine-needle aspirates of the hepatic masses included inflammation and necrosis with eosinophilic, membranous oval structures consistent with cestode infection. Histopathologic findings for biopsies of these masses included extensive necrosis, inflammation, and PAS-positive hyaline-like membranous material interpreted as metacestode cyst wall. A PCR product was generated from aspirate material using primers specific for Echinococcus multilocularis. Subsequent sequence data were 100% homologous to E. multilocularis NADH dehydrogenase subunit I gene sequences. The dog received daily oral albendazole (10 mg/kg) treatment, but its condition deteriorated, and the dog was euthanized. The dog, born in Mississippi, was brought as a puppy to Virginia with no other travel history. To our knowledge, alveolar echinococcosis has not been reported previously in a dog in the United States; E. multilocularis infection was apparently acquired in the mid-Atlantic region of the United States.

First report of pulmonary cysticercosis caused by Taenia crassiceps in a Cape fur seal (Arctocephalus pusillus)

The cestode Taenia crassiceps parasitizes in the intestine of domestic and wild carnivores, especially in red foxes. Usually, the metacestode stage, also known as Cysticercus longicollis, is located in muscles, peritoneal and pleural cavity of wild rodents. In this case, larval stages were found in a female Cape fur seal, which lived in a German zoo since June 1998. In January 2019, the animal presented clinical signs in terms of inappetence and reduced mobility and, within a short time, it developed dyspnoea and died. Pathological and parasitological examinations were performed. In a large mass of the right thoracic wall and in nodular lung lesions, metacestodes with numerous protoscoleces were identified. Morphological and molecular analyses led to the diagnosis of a Taenia crassiceps infection. Probably, the urban fox population was the source of infection. Thus, regarding the zoonotic potential of this cestode, a regularly performed parasitological examination of pet dogs is recommended.

Wildlife-transmitted Taenia and Versteria cysticercosis and coenurosis in humans and other primates

Wild mustelids and canids are definitive hosts of Taenia and Versteria spp. while rodents act as natural intermediate hosts. Rarely, larval stages of these parasites can cause serious zoonoses. In Europe, four cases of Taenia martis cysticercosis have been diagnosed in immunocompetent women, and two cases in zoo primates since 2013. In North America, a zoonotic genotype related but distinct from Versteria mustelae has been identified in 2014, which had caused a fatal infection in an orangutan and liver- and disseminated cysticercoses in two severely immune deficient human patients in 2018, respectively. Additionally, we could attribute a historic human case from the USA to this Versteria sp. by reanalysing a published nucleotide sequence. In the last decades, sporadic zoonotic infections by cysticerci of the canid tapeworm Taenia crassiceps have been described (4 in North America, 8 in Europe). Besides, 3 ocular cases from North America and one neural infection from Europe, all in immunocompetent patients, 6 cutaneous infections were described in severely immunocompromised European patients. Correspondingly, besides oral infections with taeniid eggs, accidental subcutaneous oncosphere establishment after egg-contamination of open wounds was suggested, especially in cases with a history of cutaneous injuries at the infection site. Taenia multiceps is mainly transmitted in a domestic cycle. Only five human coenurosis cases are published since 2000. In contrast, T. serialis coenurosis (1 human case since 2000) is primarily transmitted by wild canids. The etiological diagnosis of exotic cysticercoses is challenging. Usually, clinical material does not allow for a morphological identification, and serological tests are not available. These limitations have partly been overcome by molecular tools. Without claiming any dramatic emergence of cysticercoses and coenuroses transmitted by wild carnivores, further sporadic cases of such ‘exotic’ infections have to be expected.

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Wild canids and mustelids transmit rare but potentially fatal cysticercoses and coenuroses.

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Martens and weasels can rarely transmit dangerous parasitic infections.

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Tapeworm eggs may contaminate wounds and develop locally.

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In North America, the mustelid tapeworm Versteria causes severe human infections.

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Molecular analyses from minute clinical material allows for a specific diagnosis.

TAENIA CRASSICEPS CYSTICERCOSIS IN A NILGIRI LANGUR ( SEMNOPITHECUS JOHNII)

  A captive-born adult female Nilgiri langur ( Semnopithecus johnii) developed an edematous swelling of the left thigh and a firm mass around the right ankle joint. The animal also suffered from lethargy and anorexia and was euthanized because of poor general condition. Necropsy revealed that the skeletal muscle of the left thigh had been replaced by a multilocular cystic mass containing numerous sand-grain-sized whitish structures. Small cysts were also present in the lung and the myocardium. The mass of the right ankle joint was histologically consistent with a myxosarcoma. In contrast, the cystic masses from the left thigh, the lung, and the myocardium represented metacestode tissue with evidence of numerous larval cestodes consistent with cysticerci. Cysticerci showed morphological characteristics of Cysticercus longicollis, the larval form of Taenia crassiceps, which was confirmed by genetic analysis. This is the first documented case of a Taenia crassiceps cysticercosis in an Old World monkey species.

Echinococcus ortleppi, the cattle strain in a crested porcupine (Hystrix cristata): A new host record

Echinococcus granulosus sensu lato, a dog tapeworm is a species complex causing cystic echinococcosis or hydatid disease in a great variety of mammalian intermediate hosts, including humans. This complex comprises five species including Echinococcus ortleppi (G5 genotype or cattle strain). In the present paper, we report the first case of infection with the larval stage of latter cestode in a captive crested porcupine (Hystrix cristata), molecularly confirmed by PCR and sequencing of the cox1 and nad1 genes. The food contaminated with the parasite's eggs is the most likely source of the infection. Our data broaden the knowledge on the host range and geographical distribution of this rarely reported species of Echinococcus in Europe.