Molecular identification and prevalence of plerocercoid larvae (Cestoda: Diphyllobothriidae) in some commercial fish species from Peru.

Diphyllobothriosis, a fish-borne zoonosis in South America, is mainly caused by the Pacific broad tapeworm Adenocephalus pacificus Nybelin, 1931, a parasite of considerable concern in fishery resources due to its impact on public health. A new diphyllobothrid, Diphyllobothrium sprakeri Hernández-Orts et al. Parasites Vectors 14:219, 2021, was recently described from sea lions from the Pacific Coast, but marine fish acting as intermediate hosts are unknown. The objective of this study was to confirm the presence of plerocercoid larvae of Diphyllobothriidae Lühe, 1910 (Cestoda: Diphyllobothriidea) in nine fish species of commercial importance in Peru. Of a total of 6999 fish (5861 Engraulis ringens, 853 Sciaena deliciosa, 6 Sciaena callaensis, 171 Scomber japonicus, 40 Trachurus murphyi, 40 Ariopsis seemanni, 18 Merluccius peruanus, 5 Sarda chiliensis, and 5 Coryphaena hippurus), 183 were infected with plerocercoid larvae, representing a total prevalence of 2.61% and a mean intensity of 3.2. Based on mtDNA cox1 sequences of 43 plerocercoids, a phylogenetic analysis revealed that 41 belong to A. pacificus and two to D. sprakeri. These findings are first molecular data for D. sprakeri larvae, and the infections of E. ringens and T. murphyi by plerocercoid larvae represent the first records of intermediate/paratenic hosts for this species. Hence, the findings of the current study enhance our understanding of the presence of diphyllobothriid species in commercial fish from the Southeastern Pacific Ocean and their potential impact on seafood safety for local human populations.

Human diphyllobothriasis in Argentina: assessing the epidemiological significance from historical records and reports of new cases.

Between 1898 and 1940, eight human cases of diphyllobothriasis were reported in Argentina, always in recently arrived European immigrants. In 1982, the first autochthonous case was detected, and since then, 33 other autochthonous cases have been reported, totaling 42 cases of human diphyllobothriasis in Argentina before the present study. Our aim is to update the information on diphyllobothriasis in Argentina by identifying specimens from new cases using morphometrical and/or molecular methods. We also aim to assess the epidemiological relevance of this food-borne disease in the country. Anamnestic data were obtained from patients or professionals, along with 26 worms identified using morphometrical (21 samples) and molecular techniques (5 samples). All the patients acquired the infection by consuming freshwater salmonids caught in Andean lakes in Northern Patagonia. Morphometrics and DNA markers of worms were compatible with Dibothriocephalus latus. In total, 68 human cases have been detected in Argentina, 60 of which were autochthonous. The human population living North-western Patagonia, whose lakes are inhabited by salmonids, is increasing. Similarly, the number of other definitive hosts for Dibothriocephalus dendriticus (gulls) and for D. latus (dogs) is also increasing. In addition, salmonid fishing and the habit of consuming home-prepared raw fish dishes are becoming widespread. Therefore, it is to be expected that diphyllobothriasis in Argentina will increase further.

PALEOEPIDEMIOLOGY OF DIPHYLLOBOTHRIOSIS: CULTURAL AND ENVIRONMENTAL FACTORS AFFECTING ADENOCEPHALUS INTENSITY AND PREVALENCE.

Peruvian and Chilean mummies and coprolites provide a source of population-based parasitological information. This is especially true of the fish tapeworm, Adenocephalus pacificus. Our analysis of Chinchorro and Chiribaya mummies and diversified coprolite samples from Chile and Peru show variation in infection. There is a statistically significant difference in prevalence between Chinchorro hunter-gatherer and Chiribaya mixed-subsistence contexts. Furthermore, the most pronounced differences occur between populations within these groups. Chinchorro differences in cemeteries at the same location can be related to El Niño-Southern Oscillation variations. Pronounced prevalence variations between 3 Chiribaya villages within 7 km of each other relate to fish distribution and preparation variation. As with other recent archaeoparasitology studies, eggs-per-gram data exhibit overdispersion.

[Implementation of a network drug strategy: the case of praziquantel]. / Implementación de una estrategia de medicamentos en red: el caso de praziquantel.

Parasitic infections cause a huge burden of disease and are a current public health problem. The category of emerging or re-emerging disease is influenced by phenomena that occur in today's interconnected world because of globalization, the displacement of people, trade, uncoordinated urbanization and climate change, they have a very important influence on transmission of these diseases. In 2021 there was an increase in the number of patients who have required treatment for diphyllobothriasis in the Los Ríos Region. This article reviews aspects related to integrated Health Service networks to provide access to pharmacological treatments to patients diagnosed with diphyllobothriasis (tapeworm infection), implemented by the Valdivia Health Service Department, in collaboration with the San José de Osorno hospital, primary care centers and private centers in the Los Ríos Region.

Implementación de una estrategia de medicamentos en red: el caso de praziquantel / Implementation of a network drug strategy: the case of praziquantel

Resumen Las infecciones parasitarias provocan una enorme carga de enfermedad y constituyen un problema presente para la salud pública. Las enfermedades emergentes o reemergentes se ven influenciadas por fenómenos del mundo actual interconectado producto de la globalización, el desplazamiento de las personas, el comercio, la urbanización descoordinada y el cambio climático, contribuyendo en la transmisión de estas enfermedades. En el año 2021 hubo un aumento de la cantidad de pacientes que han requerido tratamiento para la difilobotriasis en la Región de los Ríos. Se revisan los aspectos relacionados con las redes integradas de servicios de salud para el acceso al tratamiento farmacológico a pacientes con diagnóstico de difilobotriasis, implementado por la Dirección de Servicio de Salud Valdivia, en colaboración con el hospital San José de Osorno, centros de atención primaria y centros privados de la Región de los Ríos.

Abstract Parasitic infections cause a huge burden of disease and are a current public health problem. The category of emerging or re-emerging disease is influenced by phenomena that occur in today's interconnected world because of globalization, the displacement of people, trade, uncoordinated urbanization and climate change, they have a very important influence on transmission of these diseases. In 2021 there was an increase in the number of patients who have required treatment for diphyllobothriasis in the Los Ríos Region. This article reviews aspects related to integrated Health Service networks to provide access to pharmacological treatments to patients diagnosed with diphyllobothriasis (tapeworm infection), implemented by the Valdivia Health Service Department, in collaboration with the San José de Osorno hospital, primary care centers and private centers in the Los Ríos Region.

A regional study of the zoonotic broad tapeworm Dibothriocephalus spp. in Northwestern Patagonia (Argentina): origin of fishes and coastal cities as factors affecting infection in fishes.

Diphyllobothriosis was first recorded in humans in Argentina in 1892 and in introduced salmonids in 1952. The aim of this work is to assess factors influencing the values of prevalence and abundance of plerocercoids in fishes that could increase the risk of transmission of Dibothriocephalus spp. in Andean Patagonian lakes. We analysed two key issues potentially related to the occurrence of tapeworms in fish: the presence of cities on coastlines (as potential sources of eggs to nearby lakes) and the difference between native and exotic fishes in susceptibility to infection. We investigated the probability of finding parasites in fish, the variation in parasite abundance in different environments and the relationship between host length and occurrence of plerocercoids. A total of 3226 fishes (belonging to six autochthonous and four introduced species) were analysed between 2010 and 2019 in eight environments. Plerocercoids were counted, and a subset was determined molecularly to species level. Two species, Dibothriocephalus latus and Dibothriocephalus dendriticus, were identified from both salmonids and native fishes, this being the first molecular confirmation of these tapeworm species parasitizing native South American fishes. Salmonids had higher levels of infection than native fishes, and these levels were higher in aquatic environments with a city on their coastline. Transmission to humans seems to occur mainly through Oncorhynchus mykiss, which showed the highest infection values and is the species most captured by fishers. Based on previous data and the present results, eggs shed by humans, dogs and gulls in cities could be the principal factors in maintaining the life cycle of this parasite in surrounding aquatic environments.

Pacific Broad Tapeworm Adenocephalus pacificus as a Causative Agent of Globally Reemerging Diphyllobothriosis.

The Pacific broad tapeworm Adenocephalus pacificus (syn. Diphyllobothrium pacificum) is the causative agent of the third most common fish-borne cestodosis among humans. Although most of the nearly 1,000 cases among humans have been reported in South America (Peru, Chile, and Ecuador), cases recently imported to Europe demonstrate the potential for spread of this tapeworm throughout the world as a result of global trade of fresh or chilled marine fish and travel or migration of humans. We provide a comprehensive survey of human cases of infection with this zoonotic parasite, summarize the history of this re-emerging disease, and identify marine fish species that may serve as a source of human infection when eaten raw or undercooked.

Diphyllobothrium sp. in Canis familiaris from the subtropical area of Argentina (Puerto Iguazú, Misiones).

This paper reports the first finding of Diphyllobothrium sp. eggs in Canis familiaris (domestic dog) from Puerto Iguazú, a subtropical city of Misiones province, Argentina. In 2013, two positive cases of Diphyllobothrium sp. eggs were detected during an annual parasitological survey of dogs. Dog feces were collected in vials containing 10% formalin and processed using Telemann's sedimentation and Sheather's flotation techniques. The two cases were detected in rural areas of the municipality. Since Misiones is not a part of the endemic area of diphyllobothriasis and given the fact that it is located in the three-border area of Argentina, Brazil and Paraguay, we consider this finding of great importance to public health. We stress the need for updating the current knowledge about the life cycle of these parasites considering the range of intermediate and definitive hosts, their zoonotic potential, and the epidemiological situation in non-endemic areas.

Prevalence, intensity, and abundance of infection and pathogenesis caused by diphyllobothriosis in vulnerable, native fish and introduced trout in Lake Panguipulli, Chile.

Diphyllobothriosis in fish from freshwater ecosystems in southern Chile was first reported in 1949. Infection by plerocercoids of Diphyllobothrium latum and Diphyllobothrium dendriticum occurs in introduced trout (Oncorhynchus mykiss) and native fish. We determined the prevalence, mean intensity, and mean abundance of seasonal infection and tissue damage produced by Diphyllobothrium spp. in native fish (Percichthys trucha, Odontesthes mauleanum, and Basilichthys australis) and introduced trout (O. mykiss) from Lake Panguipulli, Chile. Prevalence, mean intensity, and mean abundance of D. latum infection were significantly greater in trout than they were in native fish. Prevalence and mean abundance were similar in O. mauleanum and P. trucha, but they were greater than those in B. australis. Prevalence and abundance were similar among seasons between sexes for the four hosts. For all host species, except P. trucha, there was a statistically significant positive correlation between host length and the abundance of plerocercoids. Infections in muscle tissue were present in 61% of trout compared with 23% in O. mauleanum and 12% in P. trucha, suggesting a greater risk for human infection when consuming trout. In general, prevalence of infection by D. dendriticum was lower than was D. latum prevalence. Encapsulation of plerocercoids was common and severe in 71% of the trout examined. Only slight encapsulation of plerocercoids was found in the native O. mauleanum, and no encapsulation was observed in P. trucha or B. australis. The greater concentration of plerocercoids in the walls of the digestive tract of trout suggests a more-rapid immune response in trout than in native fish. The low frequency of encapsulation of plerocercoids in native fish would mean greater tissue damage in the natives than that observed in the trout because they are free to migrate among the viscera, potentially endangering these native fish populations in regions where Diphyllobothrium spp. are endemic.

First molecular identification of Diphyllobothrium dendriticum plerocercoids from feral rainbow trout (Oncorhynchus mykiss) in Chile.

Between April and June 2009, 1,075 feral rainbow trout from 10 different lakes involved with aquaculture activities in Los Lagos Region, Chile, were inspected for Diphyllobothrium species. All viscera and muscles of the fish were examined using stereomicroscopy; pyloric cecae and stomachs infected with plerocercoids were checked by histology and scanning electron microscopy. Plerocercoids of Diphyllobothrium dendriticum were confirmed by PCR and sequencing of COI and 18S rRNA + ITS1 + 5.8S rRNA + ITS2 genes for the first time in Chile. Overall prevalence of plerocercoids of D. dendriticum was 9.2% (99/1,075) in Los Lagos Region and 17.4% (99/570) for Chiloe Island. Plerocercoids were not detected in the continental lakes of the Los Lagos Region (Chapo, Rupanco, and Llanquihue). Tarahuín Lake exhibited a prevalence of 50.9% (81/159), Cucao Lake 5.1% (4/79), Natri Lake 4.7% (5/107), Huillinco Lake 3.6% (5/138), and San Antonio Lake 66.7% (4/6). Abundance was 1.1 plerocercoid larvae per fish (1,169 larvae/1,075 fish). All the plerocercoids were found encysted in the viscera of the fish. Plerocercoids were 10.9 ± 3 (7-16) mm long by 0.4 ± 0.2 (0.2-0.6) mm wide. The scolex was enlarged, with 2 bothria and a frontal pit. The body was covered with short capilliform filitriches, 4-6 mm long. The Chilean COI and 18SrRNA + ITS1 + 5.8SrRNA + ITS2 gene sequences indicated 96.34-96.52% and 99% similarity with D. dendriticum sequences, respectively. Diphyllobothrium dendriticum is reported for the first time in freshwater ecosystems as far as 43 ° S on Chiloe Island. These findings and previous reports of plerocercoids of Diphyllobothrium spp. in farmed rainbow trout at Tarahuín Lake support the putative life cycle of this parasite in lakes of southern Chile where there are aquaculture activities.

Comparative efficacy of candling and glass plate compression for detection of diphyllobothriosis in rainbow trout (Oncorhynchus mykiss) musculature.

The efficiency of the direct candling technique on fillets (candling 1) was compared with examination of cuts 4 mm thick or less (candling 2) and glass plate compression for the detection of plerocercoids of Diphyllobothrium spp. in muscles of rainbow trout, Oncorhynchus mykiss. Application of the three procedures gave the following results (percentage of infected fish/percentage of isolated plerocercoids): candling 1: 40.9/22, candling 2: 29.5/18.8, glass plate compression: 29.5/59.2, and combination of candling 1 and 2: 70.5/40.8. The combination of the three techniques yielded 100% sensitivity: 44 infected fish were detected of 77 trout examined. When different regions of the musculature were compared using the three techniques, a high density of plerocercoids and the highest percentage of infection (90.9%; 40 infected trout) were detected in the ventral musculature. Candling 1, candling 2 and glass plate compression on the ventral musculature gave the following case numbers and percentages, respectively, for the total of 44 cases: 9 (20.5%), 9 (20.5%), and 22 (50%).

Endohelminth parasites from salmonids in intensive culture from southern Chile.

A total of 228 salmonids (90 Oncorhynchus mykiss, 48 Oncorhynchus kisutch, and 90 Salmo salar) from 8 intensive aquaculture centers in the south of Chile were examined for endohelminths parasites between December 2008 and May 2009. The body cavities of 2 O. mykiss were infected by Diphyllobothrium sp. plerocercoids (prevalence: 6.7%, mean intensity: 1.0, mean abundance: 0.07) from the Lake Tarahuin hatchery on the south of Chiloé Island. Also, tetraphyllidean plerocercoids (prevalence: 3.3%, mean intensity: 1, mean abundance: 0.03) and fourth-stage larvae of Hysterothylacium aduncum (prevalence: 6.7%, mean intensity: 1, mean abundance 0.07) were observed in O. kisutch from a marine hatchery in Chiloé. The occurrences of Diphyllobothrium sp. in a lake and a tetraphyllidean plerocercoid from marine cultured salmonid in Chiloé are reported for first time. No muscular infection by helminths was recorded in the fish examined.

Possible influence of the ENSO phenomenon on the pathoecology of diphyllobothriasis and anisakiasis in ancient Chinchorro populations.

Current clinical data show a clear relationship between the zoonosis rates of Diphyllobothrium pacificum and Anisakis caused by the El Niño Southern Oscillations (ENSO) phenomenon along the Chilean coast. These parasites are endemic to the region and have a specific habitat distribution. D. pacificum prefers the warmer waters in the northern coast, while Anisakis prefers the colder waters of Southern Chile. The ENSO phenomenon causes a drastic inversion in the seawater temperatures in this region, modifying both the cool nutrient-rich seawater and the local ecology. This causes a latitudinal shift in marine parasite distribution and prevalence, as well as drastic environmental changes. The abundance of human mummies and archaeological coastal sites in the Atacama Desert provides an excellent model to test the ENSO impact on antiquity. We review the clinical and archaeological literature debating to what extent these parasites affected the health of the Chinchorros, the earliest settlers of this region. We hypothesise the Chinchorro and their descendants were affected by this natural and cyclical ENSO phenomenon and should therefore present fluctuating rates of D. pacificum and Anisakis infestations.

Molecular identification of the Diphyllobothrium species causing diphyllobothriasis in Chilean patients.

Diphyllobothriasis caused by the infection of adult Diphyllobothrium tapeworms sporadically occurs in Chile. The occurrence of the disease is closely linked to the consumption of raw or undercooked freshwater and marine fishes. Diagnosis of diphyllobothriasis has been based on laboratory examinations of the morphological characteristics of proglottids and eggs passed in the feces. Although determination of the parasite to the species level is possible through histologic examination of proglottid specimens, the parasites of patients who only discharge eggs cannot be diagnosed to the species level. Determining the species responsible for the infection of humans and other animals in affected areas is an important component of understanding the epidemiologic and enzootic characteristics of any infectious disease. We therefore compared the classification results obtained using a molecular approach with those obtained from morphological and histopathological examination of proglottids or eggs from five Chilean individuals with diphyllobothriasis. DNA analysis confirmed that the causative Diphyllobothrium species in Chile were first identified as Diphyllobothrium latum and Diphyllobothrium pacificum at least. Furthermore, mitochondrial cytochrome c oxidase subunit 1 gene analysis also supported the hypothesis that D. latum from Chile originated from Europe.

Possible influence of the ENSO phenomenon on the pathoecology of diphyllobothriasis and anisakiasis in ancient Chinchorro populations

Current clinical data show a clear relationship between the zoonosis rates of Diphyllobothrium pacificum and Anisakis caused by the El Niño Southern Oscillations (ENSO) phenomenon along the Chilean coast. These parasites are endemic to the region and have a specific habitat distribution. D. pacificum prefers the warmer waters in the northern coast, while Anisakis prefers the colder waters of Southern Chile. The ENSO phenomenon causes a drastic inversion in the seawater temperatures in this region, modifying both the cool nutrient-rich seawater and the local ecology. This causes a latitudinal shift in marine parasite distribution and prevalence, as well as drastic environmental changes. The abundance of human mummies and archaeological coastal sites in the Atacama Desert provides an excellent model to test the ENSO impact on antiquity. We review the clinical and archaeological literature debating to what extent these parasites affected the health of the Chinchorros, the earliest settlers of this region. We hypothesise the Chinchorro and their descendants were affected by this natural and cyclical ENSO phenomenon and should therefore present fluctuating rates of D. pacificum and Anisakis infestations.

Identity of Diphyllobothrium spp. (Cestoda: Diphyllobothriidae) from sea lions and people along the Pacific coast of South America.

Host specificity evidently is not expressed by various species of Diphyllobothrium that occur typically in marine mammals, and people become infected occasionally when dietary customs favor ingestion of plerocercoids. This report mainly concerns 2 species, Diphyllobothrium pacificum and Diphyllobothrium arctocephalinum, for which sea lions (Otariidae) are final hosts. The taxonomic status of those cestodes has not been clearly discernible because of misinterpretation of relationships; complex synonymies have resulted from misidentification(s). Stiles and Hassall in 1899 obtained, but did not describe, cestodes from the northern fur seal (Otariidae; Pribilof Islands). That taxon was subsequently studied by several investigators, with diverse conclusions. The valid designation is D. pacificum (Nybelin, 1931). In 1937, Johnston and Drummond described separately 2 conspecific cestodes from sea lions near Australia, designated D. arctocephalinum and Diphyllobothrium arctocephali. Both names have been listed incorrectly as synonyms of D. pacificum.

[Aquaculture and public health. The emergence of diphyllobothriasis in Chile and the world]. / Acuicultura y salud pública. La expansión de la difilobotriasis en Chile y el mundo.

Recent clinical and epidemiológical information, an analysis of the literature, and study of the technical aspects of Chilean salmon aquaculture indicate that this activity has the ability to expand the range of diphyllobothriasis caused by the fish tapeworm Diphyllobothrium latum. Evidence for expansion of the range of the fish tapeworm includes the emergences of clinical cases in Brazil related to consumption of salmon produced in Chile. Expansion of the range of this parasite is also suggested by an increase of its geographical range in Chile, beyond its previously endemic foci in the lakes of Regions IX and X. Prevention of further dissemination of this parasitic disease rests on an improvement of sanitation and sewage disposal around the lakes of Regions IX, X and XI in Chile, improvement in aquaculture methods including curtailing the use of fish tapeworm-contaminated lakes to grow juveniles forms of salmonids and more measures to decrease the number of salmonid escapees from marine pens to prevent their return to rivers and lakes carrying the infestation. Moreover, tracking the origin of juveniles in marketed salmon, determining the presence of plerocercoids in them, and increased education of the public regarding the potential dangers of eating raw fish should also be implemented. Only by stimulating the dialogue between the industry, consumers and state regulators will it be possible to implement appropriate measures to prevent further expansion of this parasitic disease by salmon aquaculture.