Human infection with an unknown species of Dracunculus in Vietnam.

Guinea worm (GW) disease, caused by Dracunculus medinensis, is an almost eradicated waterborne zoonotic disease. The World Health Organization (WHO) currently lists GW as endemic in only five African countries. In July 2020, the Vietnamese public health surveillance system detected a hanging worm in a 23-year-old male patient, who did not report any travel to Africa or any country previously endemic for GW. The patient was hospitalized with symptoms of fatigue, anorexia, muscle aches, and abscesses, with worms hanging out of the skin in the lower limbs. The worms were retrieved from the lesions and microscopically examined in Vietnam, identifying structures compatible with Dracunculus spp. and L1-type larvae. A section of this parasite was sent to the Centers for Disease Control and Prevention (CDC) in Atlanta, United States, for confirmatory diagnosis of GW. The adult worm had cuticle structures compatible with Dracunculus parasites, although the length of L1 larvae was about 339 µm, substantially shorter than D. medinensis. DNA sequence analysis of the 18S small subunit rRNA gene confirmed that this parasite was not GW, and determined that the sample belonged to a Dracunculus sp. not previously reported in GenBank that clustered with the animal-infective Dracunculus insignis and Dracunculus lutrae, located in a different clade than D. medinensis. This study highlights the importance of effective public health surveillance systems and the collaborative work of local public health authorities from Vietnam with the WHO and CDC in efforts to achieve the eradication of GW.

Patent Macracanthorhynchus ingens Infection in a 17-Month-Old Child, Ohio.

Limited data exist on human Macracanthorhynchus infections. We report an asymptomatic 17-month-old who passed eggs and an adult Macracanthorhynchus ingens worm, indicating parasite maturation and reproduction. Macracanthorhynchus ingens may have a greater capacity to mature in humans versus Macracanthorhynchus hirudinaceus.

Molecular typing of Cyclospora cayetanensis in produce and clinical samples using targeted enrichment of complete mitochondrial genomes and next-generation sequencing.

BACKGROUND: Outbreaks of cyclosporiasis, a diarrheal illness caused by Cyclospora cayetanensis, have been a public health issue in the USA since the mid 1990's. In 2018, 2299 domestically acquired cases of cyclosporiasis were reported in the USA as a result of multiple large outbreaks linked to different fresh produce commodities. Outbreak investigations are hindered by the absence of standardized molecular epidemiological tools for C. cayetanensis. For other apicomplexan coccidian parasites, multicopy organellar DNA such as mitochondrial genomes have been used for detection and molecular typing. METHODS: We developed a workflow to obtain complete mitochondrial genome sequences from cilantro samples and clinical samples for typing of C. cayetanensis isolates. The 6.3 kb long C. cayetanensis mitochondrial genome was amplified by PCR in four overlapping amplicons from genomic DNA extracted from cilantro, seeded with oocysts, and from stool samples positive for C. cayetanensis by diagnostic methods. DNA sequence libraries of pooled amplicons were prepared and sequenced via next-generation sequencing (NGS). Sequence reads were assembled using a custom bioinformatics pipeline. RESULTS: This approach allowed us to sequence complete mitochondrial genomes from the samples studied. Sequence alterations, such as single nucleotide polymorphism (SNP) profiles and insertion and deletions (InDels), in mitochondrial genomes of 24 stool samples from patients with cyclosporiasis diagnosed in 2014, exhibited discriminatory power. The cluster dendrogram that was created based on distance matrices of the complete mitochondrial genome sequences, indicated distinct strain-level diversity among the 2014 C. cayetanensis outbreak isolates analyzed in this study. CONCLUSIONS: Our results suggest that genomic analyses of mitochondrial genome sequences may help to link outbreak cases to the source.

A Second Case of Human Conjunctival Infestation With Thelazia gulosa and a Review of T. gulosa in North America.

We describe a second case of human infection caused by Thelazia gulosa (the cattle eye worm), likely acquired in California. For epidemiologic purposes, it is important to identify all Thelazia recovered from humans in North America to the species level.

Percutaneous Emergence of Gnathostoma spinigerum Following Praziquantel Treatment.

A Bangladeshi patient with prior travel to Saudi Arabia was hospitalized in the United States for a presumptive liver abscess. Praziquantel was administered following a positive Schistosoma antibody test. Ten days later, a subadult worm migrated to the skin surface and was identified morphologically as Gnathostoma spinigerum. This case highlights the challenges of gnathostomiasis diagnosis, raising questions on potential serologic cross-reactivity and the possible role of praziquantel in stimulating outward migration of Gnathostoma larvae/subadults.

Ocular Trematodiasis Caused by the Avian Eye Fluke Philophthalmus in Southern Texas.

A trematode identified as a Philophthalmus sp was extracted from the bulbar conjunctiva of a patient in southern Texas with short-distance travel to Mexico. This parasite is very rarely reported from humans, and species identification is challenging. Aspects of diagnosis, zoonotic transmission, and unresolved questions about Philophthalmus spp are discussed.

Case Report: Cervicovaginal Co-Colonization with Entamoeba gingivalis and Entamoeba polecki in Association with an Intrauterine Device.

Amoebic trophozoites were identified in the cervicovaginal smear of a U.S. patient without travel history at the time of intrauterine device (IUD) removal. Subsequent morphologic analysis and DNA sequencing identified a mixed cervicovaginal colonization of the female genital tract with both Entamoeba gingivalis and Entamoeba polecki in association with Actinomyces species bacteria. This highlights to the potential for colonization of the genital tract with E. gingivalis, particularly in association with IUD placement, and represents the first report of E. polecki in this context.

Case Report: Conjunctival Infestation with Thelazia gulosa: A Novel Agent of Human Thelaziasis in the United States.

We report a case of thelaziasis in a 26-year-old female, acquired in Oregon. A total of 14 worms were removed from the patient's left eye and were morphologically identified as being Thelazia gulosa. Until now, only two species of Thelazia have been implicated in causing human disease, Thelazia callipaeda in Asia and Europe and occasional reports of Thelazia californiensis from the United States of America. Here, we describe a third, previously unreported parasite of humans, T. gulosa (the cattle eyeworm) as an agent of human thelaziasis and the first reported case of human thelaziasis in North America in over two decades.

Comparison of Babesia microti Real-Time Polymerase Chain Reaction Assays for Confirmatory Diagnosis of Babesiosis.

Babesiosis is an emerging tick-borne disease caused by apicomplexan parasites of the genus Babesia Most human infections in the United States are caused by Babesia microti, but other infection-causing Babesia parasites have been documented as well. Polymerase chain reaction (PCR)-based methods can be used to identify this parasite to the species level. In this study, published real-time PCR assays for the specific detection of B. microti were evaluated against conventional PCR for their analytical performance. All evaluated real-time PCR assays had comparable dynamic range and amplification efficiency, but the sensitivity and specificity varied. The best performing test, a TaqMan assay targeting the 18S ribosomal RNA gene, was further evaluated for diagnostic performance using blood specimens submitted to the Centers for Disease Control and Prevention for parasite detection and was found to have 100% sensitivity and specificity. In conclusion, the 18S TaqMan real-time PCR assay is a sensitive, specific, and rapid method for identification of B. microti among cases of babesiosis in the United States.

Macracanthorhynchus ingens Infection in an 18-Month-Old Child in Florida: A Case Report and Review of Acanthocephaliasis in Humans.

A case of acanthocephaliasis in an 18-month-old child caused by Macracanthorhynchus ingens is reported from Florida. This represents only the third documented case of this species in a human host. An overview of human cases of acanthocephaliasis in the literature is presented, along with a review of the biology, clinical manifestations and pathology in the human host, morphology, and diagnosis.

Experimental transfusion-induced Babesia microti infection: dynamics of parasitemia and immune responses in a rhesus macaque model.

BACKGROUND: Babesiosis is an emerging tick-borne infection in humans. The increasing numbers of reported cases of transfusion-associated babesiosis (TAB), primarily caused by Babesia microti, represents a concern for the safety of the US blood supply. STUDY DESIGN AND METHODS: This study investigated kinetics of parasitemia and innate immune responses and dynamics of antibody responses during B. microti infection in rhesus macaques (RMs) using blood smears, quantitative polymerase chain reaction (qPCR), flow cytometry, and indirect fluorescent antibody testing. A total of six monkeys were transfused with either hamster or monkey-passaged B. microti-infected red blood cells (two and four monkeys, respectively) simulating TAB. RESULTS: The prepatent period in monkeys inoculated with hamster-passaged B. microti was 35 days compared with 4 days in monkeys transfused with monkey-passaged B. microti; the latter monkeys also had markedly higher parasitemia levels. The duration of the window period from the first detected parasitemia by qPCR analysis to the first detected antibody response ranged from 10 to 17 days. Antibody responses fluctuated during the course of the infection. Innate responses assessed by the frequencies of monocytes and activated B cells correlated with the kinetics and magnitude of parasitemia. On Day 14, additional activation peaks were noted for CD14+CD16+ and CD14-CD16+ monocytes and for CD11c+ myeloid dendritic cells, but only in animals transfused with monkey-passaged B. microti. Parasitemia persisted in these immunocompetent animals, similar to human infection. CONCLUSION: The results suggest that transfusion-associated transmission of B. microti leads to rapid onset of parasitemia (Day 4) in RMs, detectable antibody response 14 days later, and persistent parasitemia.

Review of Telemicrobiology.

CONTEXT: Microbiology laboratories are continually pursuing means to improve quality, rapidity, and efficiency of specimen analysis in the face of limited resources. One means by which to achieve these improvements is through the remote analysis of digital images. Telemicrobiology enables the remote interpretation of images of microbiology specimens. To date, the practice of clinical telemicrobiology has not been thoroughly reviewed. OBJECTIVE: To identify the various methods that can be employed for telemicrobiology, including emerging technologies that may provide value to the clinical laboratory. DATA SOURCES: Peer-reviewed literature, conference proceedings, meeting presentations, and expert opinions pertaining to telemicrobiology have been evaluated. CONCLUSIONS: A number of modalities have been employed for telemicroscopy, including static capture techniques, whole slide imaging, video telemicroscopy, mobile devices, and hybrid systems. Telemicrobiology has been successfully implemented for several applications, including routine primary diagnosis, expert teleconsultation, and proficiency testing. Emerging areas of telemicrobiology include digital plate reading of bacterial cultures, mobile health applications, and computer-augmented analysis of digital images. To date, static image capture techniques have been the most widely used modality for telemicrobiology, despite newer technologies being available that may produce better quality interpretations. Telemicrobiology adds value, quality, and efficiency to the clinical microbiology laboratory, and increased adoption of telemicrobiology is anticipated.

Draft Genome Sequences from Cyclospora cayetanensis Oocysts Purified from a Human Stool Sample.

The parasite Cyclospora cayetanensis causes foodborne diarrheal illness. Here, we report draft genome sequences obtained from C. cayetanensis oocysts purified from a human stool sample. The genome assembly consists of 865 contigs with a total length of 44,563,857 bases. These sequences can facilitate the development of subtyping tools to aid outbreak investigations.

Angiostrongylus cantonensis in Introduced Gastropods in Southern Florida.

Angiostrongylus cantonensis , the rat lungworm, is a zoonotic, parasitic nematode that uses the rat as a definitive host and gastropods as intermediate hosts. It is prevalent in parts of Asia, the Pacific islands, and the Caribbean. In the United States, A. cantonensis is established in Hawaii and in recent years has been reported in Alabama, California, Louisiana, and Florida, where it has been found in the reintroduced Lissachatina fulica (also known as Achatina fulica), the giant African snail that was once eradicated from the state. Since 2004, A. cantonensis has been identified as the causative agent for 2 non-human primate deaths in Florida, one attributed to ingestion of the snail Zachrysia provisoria. Our study further supports the presence of A. cantonensis in Z. provisoria in Florida and identifies 2 additional introduced terrestrial snails, Bradybaena similaris and Alcadia striata, that serve as intermediate hosts for A. cantonensis , as well as evidence of rat infection, in southern Florida. The finding of both definitive and intermediate hosts suggests that A. cantonensis may be established in south Florida.

Outbreak of Trichinella spiralis infections associated with a wild boar hunted at a game farm in Iowa.

BACKGROUND: Rates of trichinellosis have declined significantly in the United States due to improved pork production practices and public awareness of the danger of eating raw or undercooked pork. In April 2011, the Minnesota Department of Health received a report of presumptive trichinellosis in a 50-year-old man with a history of wild boar consumption. A public health investigation was initiated. METHODS: Medical record reviews and patient and family interviews were conducted. Trichinella species serology was performed on patient and family serum samples, and larval identification was attempted on clinical specimens and meat samples. RESULTS: The index patient harvested a wild boar from an Iowa game farm; he processed the meat after returning home and developed gastrointestinal symptoms 2 days later. Four days after his illness onset, all 5 family members consumed a roast from the boar. The index patient sought healthcare 4 times after illness onset before being definitively diagnosed with trichinellosis. Following initiation of albendazole therapy, the index patient developed atrial fibrillation. One additional family member who processed the raw meat was diagnosed with trichinellosis. Trichinella spiralis larvae were identified in wild boar meat samples. CONCLUSIONS: Trichinellosis has long been recognized as a potential hazard of consuming undercooked wild carnivore meat, and historically has been associated with consumption of pork from domestic swine, but may be unfamiliar to practicing clinicians in the United States. Education of hunters and the broader population on the potential for trichinellosis and the importance of proper handling and cooking meat from wild or free-range animals needs to be reinforced.

The occurrence of the rat lungworm, Angiostrongylus cantonensis, in nonindigenous snails in the Gulf of Mexico region of the United States.

Nonindigenous apple snails, Pomacea maculata (formerly Pomacea insularum), are currently spreading rapidly through the southeastern United States. This mollusk serves as an intermediate host of the rat lungworm parasite (Angiostrongylus cantonensis), which can cause eosinophilic meningitis in humans who consume infected mollusks. A PCR-based detection assay was used to test nonindigenous apple snails for the rat lungworm parasite in Louisiana, Texas, Mississippi, and Florida. Only apple snails obtained from the New Orleans, Louisiana, area tested positive for the parasite. These results provide the first evidence that Angiostrongylus cantonensis does occur in nonindigenous apple snails in the southeastern United States. Additionally, Angiostrongylus cantonensis was identified in the terrestrial species Achatina fulica in Miami, Florida, indicating that rat lungworm is now established in Florida as well as Louisiana. Although the study suggests that the rat lungworm is not widespread in the Gulf States region, the infected snail population could still pose a risk to human health and facilitate the spread of the parasite to new areas.

Detection of rat lungworm in intermediate, definitive, and paratenic hosts obtained from environmental sources.

Angiostrongylus cantonensis is the most common parasite causing human eosinophilic meningitis worldwide. The geographical distribution of this disease has changed dramatically in the last few decades. Various methods have been used to detect A. cantonensis in host animals around the world. A survey of mollusks collected on the island of Hawa'i in 2005 using PCR showed an infection rate of 24-78% depending on the mollusk species. In this study, samples from intermediate, definitive, and paratenic hosts were analyzed to further determine the presence of A. cantonensis in the United States. All samples were from Hawa'i, except for the apple snails (Pomacea maculata) that were collected in New Orleans, Louisiana. Angiostrongylus cantonensis was detected in the majority of species examined, including the apple snails from New Orleans and flatworms (planarians) from Hawa'i. Among the mollusks examined, the semi-slug Parmarion martensi had the highest parasite load, with an average larval burden of 445 larvae in 25 mg of tissue, as estimated by real-time PCR. In contrast, slime excreted from these highly infected mollusks contained no or very little A. cantonensis DNA. Analysis of definitive hosts (Rattus spp.) showed discrepancies between morphological and PCR-based identification; 54% of the rats were positive based on morphology, while 100% of tissue samples from these animals were positive by real-time PCR. This indicates that necropsies of rodents could underestimate the infection rates in definitive hosts of A. cantonensis.