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Our previous research on coprolite specimens from the mummies of Joseon Dynasty (1392-1910 CE) has revealed various species of parasite eggs. Herein, we added 2 new helminthic cases of human remains from Joseon-period graves in the Republic of Korea (Korea). The organic materials precipitated on the hip bones of 2 half-mummied cases (Goryeong and Gwangmyeong cases) were collected, rehydrated, and examined by a microscope. In the sample from Goryeong-gun (gun=County), ova of Trichuris trichiura, Clonorchis sinensis, and Metagonimus spp. were detected, and eggs of T. trichiura and A. lumbricoides were found from the sample of Gwangmyeong-si (si=City). By adding this outcome to the existing data pool, we confirm our previous estimates of Joseon-period parasite infection rates. The overall rates of A. lumbricoides, T. trichiura, and C. sinensis decreased dramatically from Joseon to the modern period. In Goryeong mummy specimen, we also found Metagonimus spp. eggs that has rarely been detected in archaeological samples so far.

An archaeoparasitological analysis of the soil samples from Nadym Gorodok site of Western Siberia has been carried out in this study. The archaeological site was dated as the 13 to 18th century, being characterized as permafrost region ensuring good preservation of ancient parasite eggs. Parasite eggs as Opisthorchis felineus, Alaria alata, and Diphyllobothrium sp. were found in the archaeological soil samples, which made clear about the detailed aspects of Nadym Gorodok people’s life. We found the Diphyllobothrium sp. eggs throughout the 14 to 18th century specimens, allowing us to presume that raw or undercooked fish might have been commonly used for the foods of Nadym Gorodok inhabitants and their dogs for at least the past 400 years. Our study on Nadym Gorodok specimens also demonstrate that there might have been migratory interactions and strong economic ties between the people and society in Western Siberia, based on archaeoparasitological results of Opisthorchis felineus in Western Siberia.

Although research conducted in East Asia has uncovered parasite eggs from ancient toilets or cesspits, data accumulated to date needs to be supplemented by more archaeoparasitological studies. We examined a total of 21 soil samples from a toilet-like structure at the Hwajisan site, a Baekje-period royal villa, in present-day Korea. At least 4 species of helminth eggs, i.e., Trichuris trichiura, Ascaris lumbricoides, Clonorchis sinensis, and Trichuris sp. (or Trichuris vulpis) were detected in 3 sediment samples of the structure that was likely a toilet used by Baekje nobles. The eggs of T. trichiura were found in all 3 samples (no. 1, 4, and 5); and A. lumbricoides eggs were detected in 2 samples (no. 4 and 5). C. sinensis and T. vulpis-like eggs were found in no. 5 sample. From the findings of this study, we can suppose that the soil-transmitted helminths were prevalent in ancient Korean people, including the nobles of Baekje Kingdom during the 5th to 7th century.

The aim of this parasitological study is examining contemporary (the late 20th century) specimens of the arctic or subarctic areas in Western Siberia and comparing them with the information acquired from archaeological samples from the same area. In the contemporary specimens, we observed the parasite eggs of 3 different species: Opisthochis felineus, Ascaris lumbricoides, and Enterobius vermicularis. Meanwhile, in archaeoparasitological results of Vesakoyakha, Kikki-Akki, and Nyamboyto I burial grounds, the eggs of Diphyllobothrium and Taenia spp. were found while no nematode (soil-transmitted) eggs were observed in the same samples. In this study, we concluded helminth infection pattern among the arctic and subarctic peoples of Western Siberia throughout history as follows: the raw fish-eating tradition did not undergo radical change in the area at least since the 18th century; and A. lumbricoides or E. vermicularis did not infect the inhabitants of this area before 20th century. With respect to the Western Siberia, we caught glimpse of the parasite infection pattern prevalent therein via investigations on contemporary and archaeoparasitological specimens.

Horace N. Allen, an American physician, was a Presbyterian missionary to Korea. In 1886, he wrote the annual report of the Korean government hospital, summarizing patient statistics according to outpatient and inpatient classification for the first ever in Korean history. In the report, he speculated that hemoptysis cases of outpatient might have been mainly caused by distoma. Allen’s conjecture was noteworthy because only a few years lapsed since the first scientific report of paragonimiasis. However, he was not sure of his assumption either because it was not evidently supported by proper microscopic or post-mortem examinations. In this letter, we thus revisit his assumption with our parasitological data recently obtained from Joseon period mummies.

A complicated case of echinococcosis with multiple organ involvement is reported in a 53-year-old businessman who frequently traveled overseas, including China, Russia, and Kazakhstan from 2001 to 2007. The patient was first diagnosed with a large liver cyst during a screening abdomen ultrasonography in 2011, but he did not follow up on the lesion afterwards. Six years later, dizziness, dysarthria, and cough developed, and cystic lesions were found in the brain, liver and lungs. The clinical course was complicated when the patient went through multiple surgeries and inadequate treatment with a short duration of albendazole without a definite diagnosis. The patient visited our hospital for the first time in August 2018 due to worsening symptoms; he was finally diagnosed with echinococcosis using imaging and serologic criteria. He is now on prolonged albendazole treatment (400 mg twice a day) with gradual clinical and radiological improvement. A high index of suspicion is warranted to early diagnose echinococcosis in a patient with a travel history to endemic areas of echinococcosis.

For several years, we have conducted a series of studies on the patterns of ancient parasitism prevailing in the soil of rural and urban areas of past Kingdom of Korea. Actually, during our survey of paleoparasitology in archaeological sites of Korean peninsula, numerous ancient parasite eggs were discovered in the samples from the city districts of Hansung (Joseon) and Buyeo (Baikje), the palace moat at Gyeongju (Silla), shell-midden site at Bonghwang-dong (Silla to Joseon), and the reservoir found in Hwawangsansung fortress (Silla). By the paleoparasitological studies, with respect to parasitism in the high-density populations of ancient towns and cities, we have managed to catch glimpses of the patterns prevalent therein: a serious parasitic contamination of the soil in ancient urban areas, but not in rural areas of the past. Our historical research also proposed the plausible mechanism of parasite infection very serious indeed among urban populations in Korean history. Although city dwelling doubtless has accrued significant benefits for people and populations with agriculture, it can be equally supposed that living in such highly populated areas might have facilitated the spread of parasite infection.

Analysis of ancient DNA (aDNA) extracted from Ascaris is very important for understanding the phylogenetic lineage of the parasite species. When aDNAs obtained from a Joseon tomb (SN2-19-1) coprolite in which Ascaris eggs were identified were amplified with primers for cytochrome b (cyt b) and 18S small subunit ribosomal RNA (18S rRNA) gene, the outcome exhibited Ascaris specific amplicon bands. By cloning, sequencing, and analysis of the amplified DNA, we obtained information valuable for comprehending genetic lineage of Ascaris prevalent among pre-modern Joseon peoples.

Previous paleoparasitological studies of Joseon specimens established that the prevalence of Taenia infection was not much different from that of the early 20th century Korean population. As many of taeniases originally diagnosed as Taenia saginata in South Korea were revealed to be actually Taenia asiatica, which share a common intermediate host with T. solium (the pig), Joseon people must have ingested raw pork frequently. However, the current examination of extant Joseon documents revealed that the population ate significant amounts of beef even if the beef ban was enforced; and pork was not consumed as much as we thought. Considering the meat consumption pattern at that time, Joseon people should have been infected by T. saginata more frequently than T. asiatica. This may suggest a low prevalence of T. saginata metacestodes in cattle compared to that of T. asiatica metacestodes in pigs, possibly due to the traditional way of rearing pigs (using human feces). This letter gives us a chance to reconsider the existing preconception about parasitic infections in Korean history though we are still hard to accurately estimate the historical patterns of taeniases at this stage.

Paleoparasitology is the application of conventional or molecular investigative techniques to archeological sam- ples in order to reveal parasitic infection patterns among past populations. Although pioneering studies already have report- ed key paleoparasitological findings around the world, the same sorts of studies had not, until very recently, been conduct- ed in sufficient numbers in Korea. Mummified remains of individuals dating to the Korean Joseon Dynasty actually have proved very meaningful to concerned researchers, owing particularly to their superb preservation status, which makes them ideal subjects for paleoparasitological studies. Over the past several years, our study series on Korean mummies has yield- ed very pertinent data on parasitic infection patterns prevailing among certain Joseon Dynasty populations. In this short re- view, we summarized the findings and achievements of our recent paleoparasitological examinations of Joseon mummies and discussed about the prospects for future research in this vein.

A paleoparasitological survey to detect helminth eggs was performed in archaeological sites of Jeolla-do and Jeju-do, the Republic of Korea. Total 593 soil samples were collected in 12 sites of Jeolla-do and 5 sites of Jeju-do from April to November 2011, and examined by the methods of Pike and coworkers. A total of 4 helminth eggs, 2 eggs each for Trichuris trichiura and Ascaris sp., were found in soil samples from 1 site, in Hyangyang-ri, Jangheung-eup, Jangheung-gun, Jeollanam-do. The egg-recovery layer was presumed to represent a 19th century farm, which fact suggested the use of human manures. This is the third archaeological discovery of parasite eggs in Jeolla-do. Additionally, no helminth eggs in archaeological sites of Jeju-do is an interesting problem to be solved in the further investigations.

Analysis of ancient DNA (aDNA) extracted from Ascaris is very important for understanding the phylogenetic lineage of the parasite species. When aDNAs obtained from a Joseon tomb (SN2-19-1) coprolite in which Ascaris eggs were identified were amplified with primers for cytochrome b (cyt b) and 18S small subunit ribosomal RNA (18S rRNA) gene, the outcome exhibited Ascaris specific amplicon bands. By cloning, sequencing, and analysis of the amplified DNA, we obtained information valuable for comprehending genetic lineage of Ascaris prevalent among pre-modern Joseon peoples.

In a paleo-parasitological analysis of soil samples obtained from V-shaped pits dating to the ancient Baekje period in Korean history, we discovered Ascaris lumbricoides, Trichuris trichiura, and Clonorchis sinensis eggs. In light of the samples' seriously contaminated state, the V-shaped pits might have served as toilets, cesspits, or dung heaps. For a long period of time, researchers scouring archaeological sites in Korea have had difficulties locating such structures. In this context then, the present report is unique because similar kind of the ancient ruins must become an ideal resource for successful sampling in our forthcoming paleoparasitological studies.

The rapid development of paleoparasitology in Korea has occurred in recent years, especially with discovery of mummies from the Joseon Dynasty [1,2]. When the soil sediments from Korean medieval tombs were examined for the presence of parasite eggs, we also recovered numerous eggs [3]. The ancient eggs were mostly recovered from the samples of tombs encapsulated with lime-soil mixture barrier (LSMB), which were commonly constructed for ruling class from the 15th to 19th centuries [4]. The recovered eggs mainly belonged to Trichuris trichiura and Ascaris lumbricoides, while Clonorchis sinensis, Paragonimus westermani, and Metagonimus yokogawai were occasionally found [3]. Even the larvae of Strongyloides stercoralis and the eggs of Gymnophalloides seoi were discovered in our studies [2,5]. Human taeniasis is known to be distributed worldwide, and the beef tapeworm, Taenia saginata, has been regarded as dominant over Taenia solium [6]. However, we could not discover any Taenia spp. eggs in archeological samples from Korea. Based on paleoparasitological reports from the world, the first discovery of ancient Taenia spp. eggs was from a 3,200-year-old Egyptian mummy [7]. Subsequently, taeniid eggs were reported from various archeological sites around the world. Briefly, the eggs were discovered in a mummy from a Christian Necropolis in Egypt, the embalming reject jars of Egypt, and a Han-Dynasty mummy in China [8-10]. Even the characteristic feature of cysticercosis was also reported in an Egyptian mummy from the Ptolemaic period [11]. Based on these findings, it was very unusual that taeniid eggs have not been found from archeological remains in Korea despite that Korea is known to be an endemic area for taeniasis. Even though the locality and date was not described, the prevalence of Taenia tapeworms among Koreans was quoted as 16% or 7-8% in the 1920s according to a report by Inoba in 1924, as reviewed by Eom and Rim [12]. In addition, nationwide parasitological surveys showed that the egg-positive rates for taeniasis fluctuated between 0.02% and 1.9%, even in the late 20th century [12,13]. While molecular paleoparasitological diagnosis by using PCR is sensitive enough to diagnose the parasite in a sample with only 30 parasite eggs, microscopic analysis often fails to detect small numbers of parasite eggs [14]. Hence, voluminous examination of archeological samples is needed for detection of low-density eggs when molecular diagnosis is unavailable. To confirm the negativity of Taenia spp. eggs in our archeologically-obtained collection, we re-examined the samples maintained in our collection, especially those in perfect preservation status. The sample collected from the tomb in Gongju-si was one such example, worthy of re-examination. In the tomb of Gongju-si, 2 coffins were found encapsulated with lime-soil mixture barrier (LSMB), possibly those of a husband and a wife (Fig. 1). As the husband was buried on the right side to his wife during the Joseon Dynasty, the left coffin was supposed to be that of the husband. The sample for the present study was collected from the husband's coffin, that consisted of the soil sediment spread upon the hip bones of a man living in the late 17th century. In our previous examinations, eggs of Ascaris lumbricoides, Trichuris trichiura, and Paragonimus westermani along with the larvae of Strongyloides stercoralis were detected from the left coffin [5]. This abundance of helminth ova or larvae in this sample raised hope that we might discover Taenia sp. eggs from this sample too, considering prevalence of Taenia parasitism among the Korean population. The rehydration method used in this study generally followed the method previously reported [5]. While a 400-µl of rehydrated sample was examined before, 18 ml of rehydrated sample was examined in the present study, which was nearly 45 times more than the previous examinations. Fig. 1 Two coffins, possibly those of husband and wife, were found from a tomb encapsulated with lime soil mixture barrier (LSMB) in Gongju-si, Korea. As the husband was buried on the right side to his wife during the Joseon Dynasty, the left (arrow) was supposed ... In the present study, the eggs found at first examination, i.e., A. lumbricoides, T. trichiura, and P. westermani, were also recovered (data not shown). In addition, taeniid eggs were recovered from the samples. They revealed characteristic features of taeniid eggs with a radially striated embryophore, although hooklets were not clearly observed (Fig. 2). A total of 5 Taenia spp. eggs were recovered from the sample. Since 2 of them were unmeasurable due to a partial destruction, 3 of them were photographed and measured (Fig. 2). They were 37.5-40.0 µm×37.5 µm in size, and 5.6 µm in thickness of the embryophore. Fig. 2 Three eggs of Taenia sp. found in the tomb of Gongju-si, Korea. The radially striated embryophore is seen, 5.6 µm in thickness. ×400. Bar=10 µm. This is the first discovery of taeniid eggs from archeological samples of Korea. Since species differentiation was not possible by microscopic examinations, the precise species should be evaluated further in forthcoming studies, especially by molecular studies. Considering that taeniid eggs were not found in the first examination and that only 5 Taenia eggs were discovered from all of the remaining samples at this time, intensive examination on voluminous samples will be needed for identification of Taenia eggs in archeological samples from Korea. Among the various helminth eggs, those of Taenia spp. have not frequently been discovered in archeological samples [10]. The scarcity of taeniid eggs could be explained as follows: First, the ancient taeniid eggs were usually preserved in mummies, but not in soil sediments at archeological sites [10]. In addition, among various geological strata in archeological sites of Belgium, the eggs of Taenia spp. were discovered only in those of recent days [15]. This suggested that the egg shells of Taenia spp. are fragile and not suitable for long-term preservations [9]. Second, the infection rate of Taenia spp. might be lower than that of other helminth species. In Korea, the positive rate of Taenia spp. was only 1.9% in 1971 when the overall parasite positive rate was 84.3% [16]. Third, Taenia spp. eggs escape from the uterus through the ruptured wall after the gravid proglottid becomes free from the strobila [17]. This might result in scarcity of taeniid eggs in the coprolites or soil samples. In order to find out more Taenia spp. eggs in archeological samples from Korea, we should consider that T. solium and T. asiatica, especially the latter, were prevalent in Jeju-do with its complete life cycle. The report on Jeju inhabitants showed that 27.2% of them had an experience of eating raw pig liver, more than those of any other province [12]. In fact, the taeniid infection rate of Jeju-do was 1.5% in 1992, while in other geographic areas the infection rate was ≤0.3% [16]. Furthermore, 6% of the populations on Cheju Island (Jeju-do) were suspected to carry 2 adults of T. asiatica on average in 1986 and 1987 [18], and a survey of neurocysticercosis prevalence among epilepsy patients showed that the island had the highest positive rate (8.4%) among all areas of Korea [19]. Therefore, our next paleoparasitological study must include works on samples from Jeju-do where the ancient taeniid eggs might have a greater likelihood of discovery.

While the presence of pinworm eggs in archaeological samples has been reported by many researchers in the New World, those have been detected very scarcely in the Old World, especially in East Asian countries. In fact, many parasite species were recovered from the archeological remains in Korea, eggs of Enterobius vermicularis had not been found. Recently, a female mummy buried in the 17th century was discovered in the Joseon tomb from Dangjin-gun, Chungcheongnam-do, Korea. After rehydration process for 12 days, investigations were carried on the luminal surface of the colon. From them, 3 eggs of E. vermicularis were recovered. They were elliptical, transparent with a thin egg shell, 50.3±5.2 µm (length) and 28.2±3.9 µm (width) in size. This is the first discovery of E. vermicularis eggs in East Asia.