Periodicity exhibited by Dirofilaria immitis microfilariae identified in dogs of Korea

Microfilarial periodicity of Dirofilaria immitis (the dog heartworm) was determined at two hr intervals for 72 consecutive hrs in 10 naturally infected war dogs, 3-9 years old, in Korea to facilitate harvest of the microfilariae for possible use in laboratory works and to elucidate further the periodicity of the microfilaria depending on geographic location. Although the periodicity had been observed as being low-grade nocturnal, maximal microfilarial counts were found at 21:00 hr and minimal at 11:00 hr, giving rise to an evident peak in fluctuation of the larval counts. This is the first record of the periodicity of the microfilariae identified as D. immitis in Korea.     

Plerocercoids of Nybelinia surmenicola (Cestoda: Tentacularidae) in Squids,Todarodes pacificus,from East Sea,the Republic of Korea

A visceral helminth of the squid, Todarodes pacificus, is reported from the East Sea, the Republic of Korea. Total 39 squid samples were purchased from a fish market in Jumunjin-eup, Gangneung-si (City) from August 2014 to July 2015 and were examined for helminth parasites with naked eyes and under a stereomicroscope after opening the abdominal cavity with a pair of scissors. Whitish larval worms were mainly found in the stomach and abdominal cavity of the squid. They were detected in 25 (64.1%) out of 39 squids examined, and the infection density was 7 larvae per infected squid. Spatula-shaped larvae were 8.2×2.0 mm in average size, round to slightly flattened anteriorly, with round hatching posteriorly, and had characteristic 4 tentacles with numerous hooklets in the scolex. The larvae were identified as the plerocercoid stage of Nybelinia surmenicola by their morphological features. This finding represents a new host record and the first report of N. surmenicola infection in T. pacificus squids from the east coast of Korea.     

Four human cases of Diphyllobothrium latum infection

Diphyllobothrium latum infections in 4 young Korean men detected from 2008 to 2012 are presented. Three were diagnosed based on spontaneously discharged strobila of the adult worm in their feces, and 1 case was diagnosed by finding the worm at colonoscopy examination in a local clinic. The morphologic characteristics of the gravid proglottid and eggs were consistent with D. latum. All patients were treated with praziquantel 15 mg/kg, and follow-up stool examinations were done at 2 months after the medication. The main clinical complaints were intermittent gastrointestinal troubles such as indigestion, abdominal distension, and spontaneous discharge of tapeworm's segments in their feces. The most probable source of infection was the flesh of salmon or trout according to a patient's past history. These are the 45th to 48th recorded cases diagnosed by the adult worm in the Republic of Korea since 1971.     

A Case of Oral Myiasis Caused by Lucilia sericata (Diptera: Calliphoridae) in Korea

We report here a case of oral myiasis in the Republic of Korea. The patient was a 37-year-old man with a 30-year history of Becker''s muscular dystrophy. He was intubated due to dyspnea 8 days prior to admission to an intensive care unit (ICU). A few hours after the ICU admission, 43 fly larvae were found during suction of the oral cavity. All maggots were identified as the third instars of Lucilia sericata (Diptera: Calliphoridae) by morphology. We discussed on the characteristics of myiasis acquired in Korea, including the infection risk and predisposing factors.     

A case of Diphyllobothrium latum infection with a brief review of diphyllobothriasis in the Republic of Korea

A case of Diphyllobothrium latum infection in a 49-year old man is described, and diphyllobothriasis latum in the Republic of Korea is briefly reviewed. An incomplete strobila of a tapeworm, 95 cm in length, without scolex and neck, was spontaneously discharged in the feces of a patient. On the basis of morphologic characteristics of the worm and eggs, the worm was identified as D. latum. The patient was successfully treated with a single dose (15 mg/kg) of praziquantel. The most probable source of infection was salmon flesh according to the past history of the patient. The first case of D. latum infection was documented in 1971, and this is the 43rd recorded case in the Republic of Korea. The 43 cases were briefly reviewed. The patientso main complaints were gastrointestinal troubles, such as mild abdominal pain, indigestion, and diarrhea, and discharge of tapeworm segments in the feces. The suspected infection sources included raw or improperly cooked flesh of fresh or brackish water fish, including the perch, mullet, salmon, and trout.     

An Indigenous Case of Intestinal Capillariasis with Protein-Losing Enteropathy in Korea

We encountered an indigenous case of intestinal capillariasis with protein-losing enteropathy in the Republic of Korea. A 37-year-old man, residing in Sacheon-si, Gyeongsangnam-do, admitted to the Gyeongsang National University Hospital (GNUH) due to long-lasting diarrhea, abdominal pain, anasarca, and weight loss. He recalled that he frequently ate raw fish, especially the common blackish goby (Acanthogobius flavimanus) and has never been abroad. Under the suspicion of protein-losing enteropathy, he received various kinds of medical examinations, and was diagnosed as intestinal capillariasis based on characteristic sectional findings of nematode worms in the biopsied small intestine. Adults, juvenile worms, and eggs were also detected in the diarrheic stools collected before and after medication. The clinical symptoms became much better after treatment with albendazole 400 mg daily for 3 days, and all findings were in normal range in laboratory examinations performed after 1 month. The present study is the 6th Korean case of intestinal capillariasis and the 3rd indigenous one in the Republic of Korea.     

Microphallus koreana n. sp. (Trematoda: Microphallidae) transmitted by a marine crab, Macrophthalmus dilatatus

Microphallus species occur primarily as intestinal parasites of birds and mammals, and metacercariae of a new species belonging to this genus have been discovered from the crab, Macrophthalmus dilatatus, in the Republic of Korea. The metacercaria of this fluke was round with 2 thick walls, and the excysted one had mature genital organs. The adult flukes recovered from experimentally infected chicks had numerous intrauterine eggs, well-developed pars prostatica, widely bifurcating ceca, and prominent uterine bulge. After observing internal structures, it was concluded that this species is different from any other known Microphallus spp. Based on the morphology of metacercariae and adult flukes, we describe this specimen as a new species, Microphallus koreana n. sp.     

Prevalence of dirofilarial infection in raccoon dogs in Japan.

The raccoon dog (Nyctereutes procyonoides viverrinus) is known to acquire canine heartworm (Dirofilaria immitis) infection. We surveyed the prevalence of heartworm infection in free-ranging raccoon dogs in the Nishi-Tama (Tokyo) and Kanagawa areas of Japan. A total of 75 raccoon dog carcasses, including 29 animals from the Nishi-Tama area and 46 from the Kanagawa area, were necropsied between 1992 and 1993. Eight out of 75 raccoon dogs were found to be infected (overall 10.7%). The prevalence of infection was 6 and 16% in Nishi-Tama and Kanagawa, respectively. Microfilarial production was observed in the uterus of one female adult dog.     

Successful Control of Lymphatic Filariasis in the Republic of Korea

A successful experience of lymphatic filariasis control in the Republic of Korea is briefly reviewed. Filariasis in the Republic of Korea was exclusively caused by infection with Brugia malayi. Over the past several decades from the 1950s to 2006, many investigators exerted their efforts to detection, treatment, and follow-up of filariasis patients in endemic areas, and to control filariasis. Mass, combined with selective, treatments with diethylcarbamazine to microfilaria positive persons had been made them free from microfilaremia and contributed to significant decrease of the microfilarial density in previously endemic areas. Significant decrease of microfilaria positive cases in an area influenced eventually to the endemicity of filariasis in the relevant locality. Together with remarkable economic growth followed by improvement of environmental and personal hygiene and living standards, the factors stated above have contributed to blocking the transmission cycle of B. malayi and led to disappearance of this mosquito-borne ancient disease in the Republic of Korea.     

Mass Death of Predatory Carp,Chanodichthys erythropterus,Induced by Plerocercoid Larvae of Ligula intestinalis (Cestoda: Diphyllobothriidae)

We describe here the mass death of predatory carp, Chanodichthys erythropterus, in Korea induced by plerocercoid larvae of Ligula intestinalis as a result of host manipulation. The carcasses of fish with ligulid larvae were first found in the river-edge areas of Chilgok-bo in Nakdong-gang (River), Korea at early February 2016. This ecological phenomena also occurred in the adjacent areas of 3 dams of Nakdong-gang, i.e., Gangjeong-bo, Dalseong-bo, and Hapcheon-Changnyeong-bo. Total 1,173 fish carcasses were collected from the 4 regions. To examine the cause of death, we captured 10 wondering carp in the river-edge areas of Hapcheon-Changnyeong-bo with a landing net. They were 24.0-28.5 cm in length and 147-257 g in weight, and had 2-11 plerocercoid larvae in the abdominal cavity. Their digestive organs were slender and empty, and reproductive organs were not observed at all. The plerocercoid larvae occupied almost all spaces of the abdominal cavity under the air bladders. The proportion of larvae per fish was 14.6-32.1% of body weight. The larvae were ivory-white, 21.5-63.0 cm long, and 6.0-13.8 g in weight. We suggest that the preference for the river-edge in infected fish during winter is a modified behavioral response by host manipulation of the tapeworm larvae. The life cycle of this tapeworm seems to be successfully continued as the infected fish can be easily eaten by avian definitive hosts.     

A Survey of Canine Heartworm Awareness in Grenada,West Indies

Heartworm is a common parasite of dogs in Grenada, West Indies, due to the tropical climate and large number of mosquitoes. Because Grenada is a developing country and a small island, resources and education on heartworm are limited. In an effort to raise awareness of canine heartworm and the preventive measures available, observations and surveys were performed to determine the following: (a) heartworm knowledge among Grenadian dog caregivers seeking veterinary care at the Grenada Society for the Prevention of Cruelty to Animals (GSPCA), (b) dissemination of heartworm information by GSPCA staff to Grenadian dog caregivers, and (c) reasons Grenadians are not administering heartworm prevention to their dogs. Results indicated a marked deficiency in both heartworm knowledge among Grenadian dog caregivers and heartworm knowledge acquisition and dissemination. Lack of knowledge was also cited as a major reason Grenadian dog caregivers were not using heartworm prevention. These results are currently being utilized to modify heartworm education practices at the GSPCA by incorporating Grenada-specific educational tools, with the ultimate goal of reducing illness and death by canine heartworm.     

Discovery of Maritrema jebuensis n. sp. (Digenea: Microphallidae) from the Asian Shore Crab, Hemigrapsus sanguineus, in Korea

Maritrema spp. (Digenea: Microphallidae) are parasites of birds, but have not been found in the Republic of Korea. In this study, metacercariae of Maritrema sp. were discovered in the Asian shore crab, Hemigrapsus sanguineus, caught in the mud-flats of Jebu-do, Hwasung-gun, Gyeonggi-do, and the adult flukes were confirmed by experimental infection into mice. Based on the symmetric ribbon-like vitellarium, adult flukes of Maritrema sp. were identified, but did not belong to previously described species in terms of the following morphologic characteristics: ceca reaching to the lateral wall at the anterior border of the ovary; ventral sucker larger than oral sucker; a prominent metraterm; and vitellarium forming a complete ring. Hence, we named this microphallid M. jebuensis n. sp. after the island where the second intermediate hosts were collected. From this study, it has been shown that Maritrema sp. is distributed in Korea and transmitted by the Asian shore crab, H. sanguineus.     

First Record of Cosmocephalus obvelatus (Acuariidae) in Common Gulls (Larus canus) from Gangneung,Korea

A nematode species belonging to the genus Cosmocephalus was collected from the stomach of 2 common gulls, Larus canus. The common gulls were found dead on the seaside of Gangneung City, the Republic of Korea. The worms were identified and classified by light (LM) and scanning electron microscopy (SEM) on the basis of important taxonomic characters. The nematodes were characterized by a body length 9.1-9.3 mm (males) and 15.5-15.9 mm (females) and cordons recurrent in anterior direction and anastomosing laterally at about the level of anterior quarter of the buccal cavity. The salient bicuspid deirids were located on the posterior to the cordons. Lateral alae were well-developed, extending from the level just posterior of deirids to the level about middle of the body. LM and SEM observations identified the worms as C. obvelatus. This is the first reported case of C. obvelatus infection in common gulls in Korea.     

Identification of Acanthotrema felis (Digenea: Heterophyidae) metacercariae encysted in the brackish water fish Acanthogobius flavimanus

The metacercariae of Acanthotrema felis Sohn et al., 2003 (Digenea: Heterophyidae) were discovered in a species of the brackish water fish, Acanthogobius flavimanus, in the Republic of Korea. They were experimentally fed to kittens, and adult flukes were harvested 7 days later. The adults were morphologically characterized by the presence of a bipartite seminal vesicle, the ventral sucker associated with a ventrogenital sac enclosing 3 sclerites (2 long and pointed, and 1 short and thumb-like), and an unarmed gonotyl. The adult flukes were identified as A. felis Sohn et al., 2003, and the brackish water fish A. flavimanus has been verified as one of its second intermediate hosts.     

Reemerging vivax malaria: changing patterns of annual incidence and control programs in the Republic of Korea

Changing patterns of the reemerging Plasmodium vivax malaria in the Republic of Korea (South Korea) during the period 1993 to 2005 are briefly analyzed with emphasis on the control measures used and the effects of meteorological and entomological factors. Data were obtained from the Communicable Diseases Monthly Reports published by the Korea Center for Disease Control and Prevention, and webpages of World Health Organization and United Nations. Meteorological data of Kangwon-do (Province) were obtained from local weather stations. After its first reemergence in 1993, the prevalence of malaria increased exponentially, peaking in 2000, and then decreased. In total, 21,419 cases were reported between 1993 and 2005 in South Korea. In North Korea, a total of 916,225 cases were reported between 1999 and 2004. The occurrence of malaria in high risk areas of South Korea was significantly (P > 0.05) correlated with the mosquito population but not with temperature and rainfall. Control programs, including early case detection and treatment, mass chemoprophylaxis of soldiers, and international financial aids to North Korea for malaria control have been instituted. The situation of the reemerging vivax malaria in the Republic of Korea is remarkably improving during the recent years, at least in part, due to the control activities undertaken in South and North Korea.     

A case of colonic lymphoid tissue invasion by Gymnophalloides seoi in a Korean man

A 65-year old Korean man, living in Mokpo-city, Jeollanam-do, Republic of Korea, visited a local clinic complaining of right upper quadrant pain and indigestion. At colonoscopy, he was diagnosed as having a carcinoma of the ascending colon, and thus, a palliative right hemicolectomy was performed. Subsequently, an adult fluke of Gymnophalloides seoi was incidentally found in a surgical pathology specimen of the lymph node around the colon. The worm was found to have invaded gut lymphoid tissue, with characteristic morphologies of a large oral sucker, a small ventral sucker, and a ventral pit surrounded by strong muscle fibers. This is the first reported case of mucosal tissue invasion by G. seoi in the human intestinal tract.     

Four Human Cases of Acanthotrema felis (Digenea: Heterophyidae) Infection in Korea

Acanthotrema felis is an intestinal trematode of cats originally reported from the Republic of Korea. Only 1 human case infected with a single adult worm has been previously recorded. In the present study, we report 4 human cases infected with a total of 10 worms recovered after anthelmintic treatment and purging. All 4 patients reside in coastal areas of Jeollanam-do, Korea, and have consumed brackish water fish including the gobies, Acanthogobius flavimanus. The worms averaged 0.47 mm in length and 0.27 mm in width, and had 3 sclerites on the ventrogenital sac; 1 was short and thumb-like, another was long and blunt-ended, and the 3rd was long and broad-tipped. They were identified as A. felis Sohn, Han, & Chai, 2003. Surveys on coastal areas to detect further human cases infected with A. felis are required.     

Rupture of the thoracic aorta associated with experimental Angiostrongylus vasorum infection in a dog

This note describes the sudden death of a dog by the rupture of the thoracic aorta caused by the presence of Angiostrongylus vasorum. A female mongrel canine with a history of weight loss and exhaustion died two hours after clinical examination. At necropsy, performed one hour after death, showed the presence of clotted blood in the thoracic cavity. Haemothorax was diagnosed. The thoracic aorta wall was thin, congested and an abnormal hole in the wall was detected approximately 0.5 cm from the entrance to the diaphragm. From clotted blood collected from the thoracic cavity, 224 first stage larvae (L1) and 15 adults of Angiostrongylus vasorum were recovered alive. Also, from a blood clot found in the aorta, four adult females and 47 L1 larvae were recovered alive. Possibly, this parasite was responsible for the aortic rupture and death of the animal.     

Cercaria caribbea LVIII Cable, 1963 (Digenea: Cyathocotylidae) in the Republic of Korea and its surface ultrastructure

Cercaria caribbea LVIII Cable, 1963 (Digenea: Cyathocotylidae) was detected from a brackish water gastropod species (Cerithideopsilla cingulata) in a coatal area of Shinan-gun, Jeollanam-do (Province), the Republic of Korea, and its surface ultrastructure was studied using a scanning electron microscope. The cercariae were found freely swimming or enveloped within daughter sporocysts when the snail host was mechanically broken. They were morphologically characterized by a linguiform and ventrally concave body, a long and bifurcated tail, and the presence of a holdfast (=tribocytic) organ posterior to the ventral sucker. On the whole ventral and dorsal surfaces, peg-like tegumental spines were densely distributed. Around the oral sucker, several sensory papillae, each with a short cilium, were distributed, and on the tail, sensory papillae, each with an extensively long cilium, were observed. This is the first record describing a cyathocotylid cercaria from a brackish water gastropod in the Republic of Korea.