Medullary gnathostomiasis in a white patient: use of immunodiagnosis and magnetic resonance imaging

Detection of Gnathostoma spinigerum larva in the brain with complete follow-up after surgical treatment of human neurognathostomiasis

Human gnathostomiasis is a food-borne zoonotic helminthic infection widely reported in Latin America, Asia, and Southeast Asia. Consuming raw, or under-cooked fresh-water fish is the leading cause of this helminthic infection, which is clinically characterized by signs of inflammation, itching sensation, or irritation with migratory swelling. Neurological symptoms resulting from neurognathostomiasis vary, and there is scant information due to the rareness of patient brain samples. This study aimed to demonstrate the first evidence of human neurognathostomiasis by the detection of Gnathostoma spinigerum larva in patient's brain during craniotomy, supported by histopathological, immunological and proteomic evidence. Clinical symptoms were obtained from medical history and physical examination with laboratory investigations, including magnetic resonance imaging (MRI), left temporal craniotomy, histopathology of brain tissue, and Western blot analysis, were performed to elucidate the causative pathogens for diagnosis. In addition, the host-parasite interaction of the parasite invading the patient's brain was characterized through proteomics. Histopathology revealed worms with the characteristic cuticular spines of G. spinigerum which were detected and identified. These histopathological findings were consistent with a positive Western blot showing a 24-kDa reactive-band for gnathostomiasis. Proteomic analysis revealed the presence of G. spinigerum serpin and serine protease in the patient's serum. Moreover, the leucine-rich alpha-2-glycoprotein was indicated as a systemic biomarker of early brain injury related to invasion by G. spinigerum. Therefore, our study provides the initial evidence of human neurognathostomiasis due to G. spinigerum larval invasion along with successful craniotomy and proven larval detection including complete follow-up, and the disease prognosis after surgical treatment.

Genetic characterisation of Tanqua (von Linstow, 1879) (Nematoda: Gnathostomatidae) larval forms including new host and locality records

In an unrelated study of spotted snakehead fish Channa punctata (Bloch) of family Channidae (N = 103) from Bangladesh, ten fish had taupe and clear coloured cysts attached to the intestinal mesentery. Investigation of the cysts revealed larval nematodes. The larvae were damaged and not suitable for detailed morphological study, however, key features such as tooth like projections of the pseudolabia and lateral pseudolabium were observed in specimens with undamaged cephalic regions. Molecular characterisation was undertaken and although the parasite genetic material was poor, five of the twelve nematode larvae through sequencing of the 18S ribosomal RNA gene, showed 98.17% match with sequences assigned for Tanqua tiara (accession number JF934728) deposited in GenBank. The prevalence of infection was 9.7% and the mean intensity 2.70. Tanqua has not previously been identified in fish, or from the definitive host, the Asian water monitor Varanus salvator (Laurenti, 1768) of family Varanidae (class Reptilia), in Bangladesh. Therefore, this study represents a new host and locality record for this nematode species. In many previous reports from this region, nematode larvae have been identified morphologically and assigned to a diverse range of nematode genera. Some confusion therefore exists regarding their accuracy and further investigations are required using molecular methodology to clarify the species of larval nematodes which infect edible fish in Bangladesh.

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Tanqua species identified from Channa punctata.

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New host and region record for Tanqua species in Bangladesh.

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Tanqua species identified using molecular methodology.

Integrative species delimitation and community structure of nematodes in three species of Australian flathead fishes (Scorpaeniformes: Platycephalidae)

This study aimed to determine the integrative characterisation of nematodes from three species of edible flathead fishes (Scorpaeniformes: Platycephalidae) in New South Wales, Australia, and describe nematode communities within three species of flatheads. Tiger (Platycephalus richardsoni (Castelnau); n = 20) and sand flatheads (Platycephalus bassensis (Cuvier); n = 20), sourced from the Nelson Bay area, and dusky flathead (Platycephalus fuscus (Cuvier); n = 20) from the Manning River, Taree, were examined for the presence of nematodes. The nematodes were initially classified morphologically as 12 different morphotypes belonging to the families Anisakidae (Anisakis types I, II, and III, Contracaecum type II, Terranova types I and II), Raphidascarididae (Hysterothylacium types IV, VI, VIII, and H. zhoushanense larva), and Gnathostomatidae (Echinocephalus sp. larva), Capillariidae (Capillaria sp.), followed by genetic identification through sequencing of the internal transcribed spacer (ITS-1, 5.8S, ITS-2) regions. Phylogenetic analyses revealed the evolutionary relationship between the identified larval specimens in the present study with available GenBank larval and adult nematodes. Sand flathead was 90% infected with nematodes followed by tiger flathead at 85% and dusky flathead at 15%. Nematodes infecting estuarine dusky and oceanic sand and tiger flatheads contrasted markedly. The analysis of similarities (ANOSIM) showed significant differences (p < 0.001) in the composition of taxa within nematode communities between the three species of flatheads (global R = 0.208) with the highest difference being between sand and dusky flatheads (R = 0.308, p < 0.001). The findings of the present study provide a foundation for future investigations of the community composition, life cycles, and distribution of nematode populations in edible fish in Australia and explore and clarify their significance to public health.

An Overview of Fish-borne Nematodiases among Returned Travelers for Recent 25 Years- Unexpected Diseases Sometimes Far Away from the Origin

Along with globalization of traveling and trading, fish-borne nematodiases seems to be increasing in number. However, apart from occasional and sporadic case reports or mini-reviews of particular diseases in particular countries, an overview of fish-borne nematodiasis among travelers have never been performed. In this review, we gathered fishborne nematodiasis among travelers for recent 25 years by an extensive global literature survey using appropriate keywords, e.g. travelers diseases, human infection, anisakiasis, gnathostomiasis, capillariasis, sushi, sashimi, ceviche, Gnathostoma, Pseudoterranova, Anisakis, Capillaria, etc., as well as various combinations of these key words. The Internet search engines PubMed, Medline, Google and Googler Scholar were used as much as possible, and the references of every paper were checked in order to identify useful and reliable publications. The results showed unexpectedly high incidence of gnathostomiasis and low incidence of anisakidosis. The different incidence values of the infection with several fish-borne zoonotic nematode species are discussed, as well as some epidemiological aspects of the infections. The difficulties of differential diagnosis in non-endemic countries are emphasized. It is concluded that travelers must avoid risky behaviors which can lead to infection and that physicians and health authorities must advice travelers on the risks of eating behaviors during travel.

A comparative study of neuroimaging features between human neuro-gnathostomiasis and angiostrongyliasis

Gnathostoma spinigerum and Angiostrongylus cantonensis are human parasites that can cause neurological symptoms. The human diseases produced by these parasites can usually be differentiated by clinical symptoms. The aim of this study was to report neuroimaging abnormalities detected with computed tomography (CT) and MR in patients with gnathostomiasis and angiostrongyliasis. We enrolled 15 and 12 patients with serologically proven gnathostomiasis and angiostrongyliasis, respectively, who had brain or spinal imaging done. The neuro-gnathostomiasis group had significantly more patients with intracerebral hemorrhage and myelitis patterns. The angiostrongyliasis group had no specific findings and most patients had normal CT brain images. The variety of neuroimaging findings is shown here. This study emphasizes that neuroimaging studies may be useful to differentiate gnathostomiasis and angiostrongyliasis particularly in patients with indistinct clinical presentations.

Gnathostomiasis, another emerging imported disease

Gnathostomiasis is a food-borne zoonosis caused by the late-third stage larvae of Gnathostoma spp. It is being seen with increasing frequency in countries where it is not endemic and should be regarded as another emerging imported disease. Previously, its foci of endemicity have been confined to Southeast Asia and Central and South America, but its geographical boundaries appear to be increasing, with recent reports of infection in tourists returning from southern Africa. It has a complex life cycle involving at least two intermediate hosts, with humans being accidental hosts in which the larvae cannot reach sexual maturity. The main risks for acquisition are consumption of raw or undercooked freshwater fish and geographical exposure. Infection results in initial nonspecific symptoms followed by cutaneous and/or visceral larva migrans, with the latter carrying high morbidity and mortality rates if there is central nervous system involvement. We review the literature and describe the epidemiology, life cycle, clinical features, diagnosis, treatment, and prevention of gnathostomiasis.

Update on eosinophilic meningoencephalitis and its clinical relevance

Eosinophilic meningoencephalitis is caused by a variety of helminthic infections. These worm-specific infections are named after the causative worm genera, the most common being angiostrongyliasis, gnathostomiasis, toxocariasis, cysticercosis, schistosomiasis, baylisascariasis, and paragonimiasis. Worm parasites enter an organism through ingestion of contaminated water or an intermediate host and can eventually affect the central nervous system (CNS). These infections are potentially serious events leading to sequelae or death, and diagnosis depends on currently limited molecular methods. Identification of parasites in fluids and tissues is rarely possible, while images and clinical examinations do not lead to a definitive diagnosis. Treatment usually requires the concomitant administration of corticoids and anthelminthic drugs, yet new compounds and their extensive and detailed clinical evaluation are much needed. Eosinophilia in fluids may be detected in other infectious and noninfectious conditions, such as neoplastic disease, drug use, and prosthesis reactions. Thus, distinctive identification of eosinophils in fluids is a necessary component in the etiologic diagnosis of CNS infections.

[Gnathostomiasis: an emerging parasitic disease?]

INTRODUCTION

Human gnathostomiasis is a parasitic disease caused by the ingestion of foods contaminated with the larvae of various species of Gnathostoma. This zoonosis is currently endemic in Asia and Central America.

CASE REPORT

A 46-year-old French woman resident in Vietnam presented with intermittent pruritic swelling of the hand, present for one year, coupled with eosinophilia. The patient's history and serological testing confirmed the suspected diagnosis of gnathostomiasis. A favorable outcome was attained on treatment with albendazole.

DISCUSSION

This case, together with several others recently reported in France and Europe, underlines the need to inform travelers and migrants to endemic regions of the risks associated with eating raw or marinated fish.

Sushi delights and parasites: the risk of fishborne and foodborne parasitic zoonoses in Asia

Because of the worldwide popularization of Japanese cuisine, the traditional Japanese fish dishes sushi and sashimi that are served in Japanese restaurants and sushi bars have been suspected of causing fishborne parasitic zoonoses, especially anisakiasis. In addition, an array of freshwater and brackish-water fish and wild animal meats, which are important sources of infection with zoonotic parasites, are served as sushi and sashimi in rural areas of Japan. Such fishborne and foodborne parasitic zoonoses are also endemic in many Asian countries that have related traditional cooking styles. Despite the recent increase in the number of travelers to areas where these zoonoses are endemic, travelers and even infectious disease specialists are unaware of the risk of infection associated with eating exotic ethnic dishes. The aim of this review is to provide practical background information regarding representative fishborne and foodborne parasitic zoonoses endemic in Asian countries.

[Gnathostomosis, an exotic disease increasingly imported into Western countries]

AN INCIDENTAL HELMITHIASIS IN MAN: Gnathostomiasis is an helminthic disease of animals due to a nematode belonging to the gender Gnathostoma. This gender includes many species, the most frequent being Gnathostoma spinigerum. Man is an incidental host. Human gnathostomiasis is endemic in some countries of South-East Asia, and Latin America. It is due to the consumption of raw or insufficiently cooked meat or fish. Since the beginning of the eighties, there is an increasing number of cases of gnathostomiasis described in Western countries in travellers returning from endemic countries. IN THE SKIN OR THE VISCERA: Gnathostomiasis is a cause of cutaneous and/or visceral larva migrans syndrome. Some visceral involvement, more particularly neurological forms, may lead to significant morbidity and mortality. The diagnosis is occasionally confirmed by the identification of the Gnathostoma larva in the skin or viscera. Most often the diagnosis relies on epidemiological, clinical and biological (hypereosinophilia, positive serologic test) grounds. ALBENDAZOLE AND IVERMECTINE: The first line treatment is albendazole, 400 mg once or twice a day during 21 days. The efficacy of ivermectin needs to be assessed more precisely. Relapses may occur up to 24 months after apparent cure.

Cutaneous and medullar gnathostomiasis in travelers to Mexico and Thailand

Gnathostomiasis is a rare nematode disease acquired by travelers to endemic areas. The most common clinical presentations are cutaneous forms; however, neurologic involvement can also occur. We present two cases of gnathostomiasis, one of them with severe neurologic complications, in Spanish travelers to Thailand and Mexico, who consumed local food and became infected.

Albendazole: a new drug for human parasitoses

In 1961 Brown and his team discovered that thiobendazoles were highly effective against gastrointestinal nematodes. This discovery led to the development of albendazole, the most recent of the benzimidazolic drugs. Albendazole is used against numerous animal and human parasites and it is the authors' first choice as drug treatment of cutaneous larva migrans.

Imported cutaneous gnathostomiasis: report of five cases

Gnathostomiasis has rarely been described outside endemic countries. We report on a series of 5 patients (4 females, 1 male, mean age 42.2 years) who returned to France from South-East Asia and presented with cutaneous gnathostomiasis. The cutaneous lesions appeared within a mean period of 62 d (range 10-150 d) after return. They consisted of creeping eruptions in 3 patients (in addition one also had papules, one had nodules and hepatitis, and one had hepatitis; all 3 had profound asthenia) and recurring migratory swellings in 2 patients. The mean eosinophil count was 1546/mm3 (range 398-3245/mm3). Diagnosis was based on positive serological tests in 3 patients and seroconversion in 2 patients, and was confirmed by identification of Gnathostoma hispidum in a biopsy specimen from one of the seropositive patients. Albandazole (1-4 courses) was given as treatment. Recurrences may occur up to 24 months after apparent cure without reinfection. Gnathostomiasis should be considered when patients return from tropical countries and present with migratory swellings or creeping eruption that does not respond to the usual treatment for cutaneous larva migrans. Serological tests may be negative initially and thus need to be repeated to check for seroconversion. Treatment may require multiple courses of albendazole and a prolonged period of follow-up is necessary before cure can be confirmed.

Eosinophilic meningitis

Eosinophilic meningitis is a rare clinical entity that can be useful in narrowing the differential diagnosis of central nervous system disease. It is defined by the presence of 10 or more eosinophils/microL in the cerebrospinal fluid (CSF) or a CSF eosinophilia of at least 10%. The most common cause is invasion of the central nervous system by helminthic parasites, particularly Angiostrongylus cantonensis, but other infections as well as noninfectious conditions may also be associated. This review describes the etiologies of eosinophilic meningitis, focusing primarily on the helminths that cause CSF eosinophilia.

Albendazole: a broad spectrum anthelminthic for treatment of individuals and populations

PURPOSE OF REVIEW

It is over 25 years ago since the original animal research was conducted into albendazole. This review highlights some important steps in fundamental research and the management of helminth disease that have occurred in the past year, appearing in the published literature.

RECENT FINDINGS

In recent years there have been several published studies on lymphatic filariasis and on the impact of albendazole treatment on growth and nutrition. Recent work consolidates some of these data and supplies substantive evidence of benefit especially in the area of hookworm anaemia. Why treatment of helminths actually produces these effects has not been understood, but investigations have begun to highlight the underlying mechanisms that relate to immunity. During the last year several reviews of diagnosis and management of helminth diseases have been published which provide much needed guidance on the effective use of albendazole, and its place in treatment overall. In common with many other parasitic diseases, the validity of using single agents is being challenged, and combination therapy is being investigated at the experimental level and in clinical practice to improve therapeutic responses and to reduce the risk of resistance to the limited range of drugs currently available.

SUMMARY

Albendazole has changed from being a drug for individuals with worms to one to treat communities and provide benefit in public health terms. In systemic parasitic disease, however, albendazole remains a treatment for individuals. Nearly 20 years of research and of clinical use has refined the tool, but new investigations suggest that much additional study is required before we fully understand helminth parasites and the benefits of treating them.

Eosinophilic meningitis due to Gnathostoma spinigerum

We present a case of eosinophilic meningitis due to the tissue nematode Gnathostoma spinigerum in a patient with remote travel to Korea. G. spinigerum is found primarily in Southeast Asia, but cases are being increasingly diagnosed in non-endemic areas because of more extensive international travel. The organism has been known to persist in human tissues for over a decade, so earlier travel to endemic areas is important.