P-1770. Epidemiological Trends of Kudoa septempunctata Food Poisoning in Japan, 2013–2023

Kudoa septempunctata, a parasite found in olive flounder, poses a growing food safety risk in East Asia, particularly in Japan and South Korea. K. septempunctata poisoning caused by raw fish consumption causes brief gastrointestinal symptoms. However, long-term, national-scale aggregated epidemiological data for K. septempunctata food poisoning are limited. In this retrospective study, we examined the recent epidemiological trends and characteristics of K. septempunctata food poisoning cases reported in Japan between January 2013 and December 2023. Ministry of Health "Foodborne Illness Statistical Data" were assessed for case counts, outbreaks, and implicated foods. Reported cases totaled 2009, reaching a peak in 2014 (429 cases) then declining to < 100 cases during the COVID-19 pandemic. October had the highest number of monthly reports. Flounder, particularly sashimi and sushi, were implicated in 99% of cases. The highest case counts occurred in Yamaguchi, Osaka, and Fukuoka prefectures (160, 155, and 154, respectively). Tottori, Shimane, Yamaguchi and Oita prefectures had the highest incidence rates (14.3, 10.9, 10.7, and 10.7 per 1,000,000 population, respectively). Prefectures along the Sea of Japan typically reported higher incidence rates. This study highlights the importance of continued surveillance and reporting of K. septempunctata poisoning, and the need to consider Kudoa infections in the differential diagnosis of food poisoning cases involving raw fish consumption.

A variety of tunas of the genus Thunnus are consumed daily in Japan as sliced raw fish (sashimi and sushi). The consumption of fresh sliced raw fish, i.e., unfrozen or uncooked, can sometimes cause food poisoning that is manifested by transient diarrhea and vomiting for a single day. One of the causes of this type of food poisoning has been identified as live Kudoa septempunctata (Myxosporea: Multivalvulida) in the olive flounder (Paralichthys olivaceus). Furthermore, raw slices of fresh tunas are highly suspected to be a possible causative fish of similar food poisoning in Japan. In the present study, we conducted a survey of kudoid infections in tunas (the yellowfin tuna Thunnus albacares, the Pacific bluefin tuna Thunnus orientalis, and the longtail tuna Thunnus tonggol) fished in the western Pacific Ocean off Japan and several East Asian countries and characterized morphologically and genetically the kudoid myxospores in pseudocysts or cysts dispersed in the trunk muscles. Pseudocysts of solely Kudoa hexapunctata were identified in the Pacific bluefin tuna (four isolates), whereas in the yellowfin tuna (21 isolates) pseudocysts of Kudoa neothunni and K. hexapunctata were detected at a ratio of 15:6, respectively, in addition to cyst-forming Kudoa thunni in five yellowfin tunas. In the trunk muscles of six longtail tunas examined, pseudocysts of K. neothunni (all six fish) and K. hexapunctata (two fish) were densely dispersed. The myxospores of K. neothunni found in these longtail tunas had seven shell valves and polar capsules (SV/PC) instead of the more common six SV/PC arranged symmetrically. Nucleotide sequences of the 18S and 28S ribosomal RNA gene (rDNA), some with the internal transcribed spacer regions as well, of K. hexapunctata and K. neothunni from the three Thunnus spp., including the seven-SV/PC morphotype, were very similar to previously characterized nucleotide sequences of each species, whereas the 18S and 28S rDNA of four isolates of K. thunni from yellowfin tunas showed a range of nucleotide variations of 99.0-99.9% identity over 1752-1763-bp long partial 18S rDNA and 97.4-99.9% identity over 797-802-bp long partial 28S rDNA. Therefore, this rather high variation of the rDNA nucleotide sequences of K. thunni proved to be contrary to the few variations of K. neothunni and K. hexapunctata rDNA nucleotide sequences. The present study provides a new host record of the longtail tuna for K. neothunni and K. hexapunctata and reveals a high prevalence of the seven-SV/PC myxospore morphotype of K. neothunni in this tuna host.

Recently, horse meat (basashi) contaminated with Sarcocystis spp. caused food poisoning in Japan. An official detection method provided by the Ministry of Health, Labour and Welfare (MHLW), Japan, was designed to detect Sarcocystis fayeri to diagnose and control outbreaks of basashi food poisoning. In 2011, Sarcocystis-contaminated venison also caused food poisoning. However, the official MHLW detection method was not adequate for detecting Sarcocystis spp. in venison. In this study, we established a novel PCR-based detection method that amplifies 18S rRNA gene based on the conserved region of the sequence in 32 species of Sarcocystis for screening and quantification. Fifty venison samples from three areas in Hokkaido were examined by the MHLW method and the novel detection method. All samples were Sarcocystis spp.-positive. A sequence analysis indicated the presence of a species of Sarcocystis specific to sika deer (Cervus nippon), and not to horses. Another primer pair was designed for a quantitative real-time PCR assay to determine the copy number of the Sarcocystis-18S rRNA gene in parasitized venison. The melting curve analysis revealed high specificity of this assay. The calculated curve demonstrated that this quantitative PCR assay showed R2 value of 0.993 with 10-106 copies. Using this quantitative real-time PCR assay, the gene copy numbers were determined in 50 venison samples. The copy numbers of each sample ranged from 104 to 107 per gram. The copy numbers differed according to the area in Hokkaido. This indicates that the density of Sarcocystis spp. that infect Sika deer in Hokkaido is affected by the area. The novel screening and quantitative PCR method for Sarcocystis in venison was useful for collecting epidemiological information on Sarcocystis in wild Japanese sika deer, which will contribute to improve the safety of venison products in Japan.

According to the annual food poisoning statistics compiled by the Ministry of Health, Labour and Welfare (MHLW) in Japan, Campylobacter replaced Salmonella and Vibrio parahaemolyticus as the leading bacterium responsible for food poisoning in 2003. Although in 2006 the number of cases of Campylobacter food poisoning was 3,439 on the basis of the MHLW statistics, it was estimated to be 1,545,363 on the basis of active surveillance, suggesting that passive surveillance yields an incidence about 450 times lower than that revealed by active surveillance. Epidemiological investigations of Campylobacter food poisoning in Japan have shown that chicken meat and its products are the most important sources of infection, as is the case in other industrialized nations. Over the last two decades, the consumption of fresh raw chicken meat and liver has been increasing in Japan. Although the MHLW recommends that chicken meat should only be eaten after thorough cooking, it is likely to account for much of the increased incidence of human campylobacteriosis. In response to this situation, the Expert Committee on Microorganisms/Viruses, Food Safety Commission of Japan, Cabinet Office, Government of Japan (FSCJ) has revised the previous risk profile of C. jejuni/coli in chicken meat by adding new findings for 2018. Moreover, the MHLW revised the Poultry Slaughtering Business Control and Poultry Meat Inspection Act in 2014 aiming at stepwise introduction of the Hazard Analysis Critical Control Point (HACCP) system into poultry processing plants. Subsequently, the Japanese government amended the Food Sanitation Act in 2018, requiring all food business operators to implement hygiene control based on HACCP principles as a general rule. This paper reviews the current status of Campylobacter food poisoning due to consumption of chicken meat in Japan and extracts the issues underlying each step of the food supply chain in order to examine the implementation of effective measures for risk management.

The Kurokashiwa breed of native Japanese chickens is primarily reared in Shimane and Yamaguchi Prefectures, Japan. To reveal the genetic diversity and differentiation among the Kurokashiwa populations in both prefectures, 29 microsatellites were analyzed. To prepare the microsatellites, 54, 55, and 24 blood samples were collected from the Kurokashiwa populations of five fancy breeders in Shimane Prefecture, three fancy breeders in Yamaguchi Prefecture, and the Livestock Technology Research Department, Yamaguchi Prefectural Agriculture and Forestry General Technology Center (LTRDY), respectively. The corrected number of alleles (allelic richness: AR) was considerably low (1.63-2.48) through all Shimane and Yamaguchi populations. However, inbreeding coefficient (F-IS) values were not significant in the entire Shimane and Yamaguchi ornamental populations as well as the LTRDY population. In addition, there was no statistically significant difference in expected heterozygosity (H-E) through all populations in Shimane and Yamaguchi Prefectures, although the H-E varied from 0.237 to 0.445 depending on populations. The topology of the phylogenetic tree, pairwise F-ST values, and STRUCTURE analysis indicated that Kurokashiwa populations were genetically separated between Shimane and Yamaguchi Prefectures. On the other hand, there was no genetic differentiation among ornamental populations within each prefecture, which seemed to have resulted from adequate random matings by exchanging individuals among fancy breeders within each conservation community, along with a proper random mating within LTRDY. The present study proposes a conservation strategy suggesting that the Kurokashiwa populations of Shimane and Yamaguchi Prefectures should be maintained separately with continuous exchange of birds within each conservation community to preserve genetic diversity. Also, the LTRDY population should be independently kept by avoiding matings with ornamental bird populations because it is a well established closed colony with a uniform genetic constitution.

The aim of the present work was to estimate quantitatively by a microslide method the amounts of enterotoxins (ET) A, B and C produced by strains of Staph. aureus associated (13 strains) and not associated (200 strains) with food poisoning.The geometric means of estimated amounts of ET-A, ET-B and ET-C produced in brain-heart infusion broth by strains associated with food poisoning were 1.67±0.08, 1.13±0.14 and 1.75±0.07μg per milliliter and those of strains not associated with food poisoning were 0.76±0.10, 1.56±0.09 and 0.98±0.09μg per milliliter, respectively. The differences in amounts of ET-A, ET-C and ET (A+B+C) between strains associated with food poisoning and strains not associated with food poisoning, were statistically significant.It was observed that the amount of ET (A+B+C) produced by strains associated with food poisoning was more than 3.0μg/ml. On the other hand, 80 of 200 strains not associated with food poisoning produced more than 3.0μg ET (A+B+C)/ml. The distribution of coagulase types observed in the 80 strains was the same pattern as that of the 200 strains. However, the coagulase types of strains (31 out of 80 strains) which produced ET-A were II, III, VI and VII. These results are consistent with reports indicating that only strains having coagulase types II, III, VI and VII were associated with food poisoning, and furthermore that the type of ET identified in cases of food poisoning in Japan and England was almost exclusively ET-A type.

Campylobacter jejuni is one of the major bacterial strains that cause diarrhea in humans. It has been associated with many cases of food poisoning in Japan caused by eating raw, undercooked, and/or improperly prepared chicken meat, liver, and grilled chicken (Yakitori). Campylobacter jejuni is also known to be a preceding infectious pathogen of Guillain-Barré syndrome (GBS), which has a considerably negative health impact on humans. In a case of C. jejuni food poisoning that occurred at a restaurant in Tokyo (Japan) in January 2022, 1 of 4 patients with diarrhea developed GBS, which was presumed to have been caused by undercooked chicken, which has emerged as one of the most common causes of food poisoning in Japan. Moreover, C. jejuni isolates from 3 patients, including those with GBS, had the same genotypes (ST22, HS19, and LOS A). This genotype was frequently detected in patients with GBS in the authors' previous study. Findings confirmed that the patient developed GBS due to food poisoning after consuming undercooked chicken.

Kuwazuimo (Alocasia odora) and shimakuwazuimo (Alocasia cucullata) are evergreen perennial plants that originated in East Asia. Although inedible, they are occasionally eaten by mistake because they resemble satoimo (Colocasia esculenta), and this has caused food poisoning in Japan. It is not easy to determine the cause of a food poisoning outbreak from the shape or chemical composition when the available sample is small. Therefore, we developed a new primer pair for PCR to identify kuwazuimo and shimakuwazuimo in small samples, based on the internal transcribed spacer (ITS) region of ribosomal DNA. Using PCR with the developed primer pair, we detected all samples of kuwazuimo obtained from the market, while excluding 17 other kinds of crops. The samples were identified as shimakuwazuimo by DNA sequencing of the PCR products. The present PCR method showed high specificity and was confirmed to be applicable to the identification of kuwazuimo and shimakuwazuimo from various crops.

Histamine poisoning has been reported worldwide. Improvements in refrigeration technology have led to a reduction in this food poisoning; however, it continues to occur. Misdiagnosis of fish allergies has compounded this problem and the number of patients subjected to histamine poisoning that are transported to the emergency ward because of anaphylactic shock-like symptoms should not be underestimated. We investigated incidents of histamine food poisoning in Japan from 1998 to 2020, and found that there were a mean 9.7 incidents/year and 195.3 cases/year. Facility-wise occurrence of the incidents per year was the highest in restaurants followed by lunch facilities, and these together accounted for approximately 70% of the incidents. Facility-wise total number of cases was the highest in lunch facilities followed by restaurants, and these together accounted for 80% of the cases. Fish associated with histamine poisoning were mainly tuna, marlin, and mackerel. Based on the current literature review, 23 genera of histamine-producing bacteria were isolated from fish purchased in Japan. The most frequently reported bacteria were Morganella morganii and Photobacterium damselae. Psychrophilic bacteria such as Morganella psychrotolerans and Photobacterium phosphoreum were also isolated. To prevent histamine poisoning, freezing or fast handling of fish and the products during processing and consuming is important because only refrigeration of fish is enough.

Vibrio parahaemolyticus food poisoning, is the most prevalent among bacterial food poisoning in Japan. Study of epidemiologic markers is important in an attempt to trace the source of contamination. The purpose of this study was to compare seven different typing methods (serotyping, plasmid profile, antibiogram, phage susceptibility. TDH production, tdh and trh gene and pulsed-field gel electrophoresis [PFGE]) for V. parahaemolyticus. Outbreaks of V. parahaemolyticus food poisoning which occurred during the 13 years from 1981 to 1993 numbered 43 including 481 cases in Nagano Prefecture. Serovar O4:K8 was the most prlevalent serovar isolated, serovar O2:K3, O4:K63 and O3:K5 followed. Forty one strains of V. parahaemolyticus were used in this study. All of the strains were isolated from 12 food poisoning cases at Nagano Prefectual Research Institute for Health and Pollution. Of the 41 strains, twenty two strains (O4:K8, O4:K63) were sensitive to both phi VP 253 and phi VP 143 phages, six strains (O3:K5) to phage phi VP 143. Thirteen strains (O3:K29, O4:K11, O4:K12 and O5:KUT) were insensitive to both phages. CBPC, CBPC.CEZ and CBPC.CEZ.KM.SM resistant strains was determined in 22 strains out of 41 strains. Five strains of V. parahaemolyticus carried plasmid. Of the 41 strains, thirty nine strains were possessive to tdh gene and productive to TDH. Chromosomal DNA of the isolates from 12 different outbreaks was analysed by PFGE after Not I digestion. PFGE analysis of the digested DNA yielded 11 to 21 DNA fragments. Twelve distinctive fragment patterns were identified in 41 V. parahaemolyticus isolates from 12 different food poisonings. These results showed that the PFGE method is an useful tool to analyse an epidemiological survey for isolates of Vibrio parahaemolyticus food poisoning.

Strains of Vibrio parahaemolyticus, the etiologic agent of "Shirasu" food poisoning in Japan, were isolated from moribund blue crabs Callinectes sapidus and identified by biochemical and serological techniques.

A myxozoan parasite Kudoa septempunctata causing the food poisoning of humans which consume raw olive flounder Paralichthys olivaceus has become a new threat to public health. ​This review focuses the recent occurrence of K. septempunctata-induced food poisoning in Japan for 10 years, the typical symptoms of the foodborne disease in humans, parasitology, diagnoses, countermeasures and the remaining issues. ​The numbers of K. septempunctata-induced cases and patients have peaked in 2014, followed by a gradual decrease in recent years. ​The symptoms of humans are characterized by transient vomiting and diarrhea. ​Also, onset of the disease is dose-dependent of fresh spores (> 1 × 107). ​The host fish for K. septempunctata is mainly limited to P. olivaceus. ​The geographical distribution is Japan and Korea. ​The two locality isolates are easily differentiated by a ratio of spores possessing 7 polar capsules. ​The light-microscopy, conventional or real-time PCRs, LAMP, immunochromatography have been developed for the diagnostic tools. ​To prevent the infection with K. septempunctata in juvenile stage of cultured flounder, a sand-filtration combined with ultraviolet irradiation (> 46 mJ/cm2) is effective. ​At the time of shipment of adult flounder, light-microscopic examination for spores is recommended to remove the infected fish group. ​The remaining problems include the disease mechanisms in humans, the host range, and the harmful Kudoa species other than K. septempunctata.

A fatal case of puffer poisoning in an 80-year-old man is reported. By using a bioassay with mice and extracts of crude poisons, the toxicities of the autopsy materials, fresh puffer ovaries, and the remaining cooked ovaries were determined and expressed in mouse units per gram (M.U.). Some medicolegal aspects of puffer poisoning are also discussed. Puffer poisoning is a primary cause of fatal food poisoning in Japan even though its frequency is not high.

Food intoxication and mosquito-borne infections remain two of the most significant public health threats globally, disproportionately affecting vulnerable populations such as children, pregnant women, older adults, low-income communities, migrants, and immunocompromised individuals. While food intoxication arises from ingestion of preformed toxins produced by microbial agents, mosquito-borne infections such as dengue, malaria, chikungunya, Zika, and West Nile virus—are transmitted through infected vectors. Both categories of diseases share common determinants: poor hygiene, inadequate sanitation, environmental degradation, weak immune status, malnutrition, and limited access to healthcare. This review provides a holistic synthesis of the underlying mechanisms, risk factors, epidemiological trends, clinical manifestations, and preventive strategies related to food intoxication and mosquito-borne infections. Emphasis is placed on socio-economic vulnerability, climate change, food insecurity, and nutrition-related susceptibility. The review highlights the need for multidisciplinary public health approaches integrating environmental management, food safety practices, vector control, community awareness, and policy-level interventions.

Lyme disease is the most commonly reported vectorborne disease in the United States but is geographically focal. The majority of Lyme disease cases occur in the Northeast, mid-Atlantic, and upper Midwest regions. Lyme disease can cause varied clinical manifestations, including erythema migrans, arthritis, facial palsy, and carditis. Lyme disease occurs most commonly among children and older adults, with a slight predominance among males. 2008-2015. Lyme disease has been a nationally notifiable condition in the United States since 1991. Possible Lyme disease cases are reported to local and state health departments by clinicians and laboratories. Health department staff conduct case investigations to classify cases according to the national surveillance case definition. Those that qualify as confirmed or probable cases of Lyme disease are reported to CDC through the National Notifiable Diseases Surveillance System. States with an average annual incidence during this reporting period of ≥10 confirmed Lyme disease cases per 100,000 population were classified as high incidence. States that share a border with those states or that are located between areas of high incidence were classified as neighboring states. All other states were classified as low incidence. During 2008-2015, a total of 275,589 cases of Lyme disease were reported to CDC (208,834 confirmed and 66,755 probable). Although most cases continue to be reported from states with high incidence in the Northeast, mid-Atlantic, and upper Midwest regions, case counts in most of these states have remained stable or decreased during the reporting period. In contrast, case counts have increased in states that neighbor those with high incidence. Overall, demographic characteristics associated with confirmed cases were similar to those described previously, with a slight predominance among males and a bimodal age distribution with peaks among young children and older adults. Yet, among the subset of cases reported from states with low incidence, infection occurred more commonly among females and older adults. In addition, probable cases occurred more commonly among females and with a higher modal age than confirmed cases. Lyme disease continues to be the most commonly reported vectorborne disease in the United States. Although concentrated in historically high-incidence areas, the geographic distribution is expanding into neighboring states. The trend of stable to decreasing case counts in many states with high incidence could be a result of multiple factors, including actual stabilization of disease incidence or artifact due to modifications in reporting practices employed by some states to curtail the resource burden associated with Lyme disease surveillance. This report highlights the continuing public health challenge of Lyme disease in states with high incidence and demonstrates its emergence in neighboring states that previously experienced few cases. Educational efforts should be directed accordingly to facilitate prevention, early diagnosis, and appropriate treatment. As Lyme disease emerges in neighboring states, clinical suspicion of Lyme disease in a patient should be based on local experience rather than incidence cutoffs used for surveillance purposes. A diagnosis of Lyme disease should be considered in patients with compatible clinical signs and a history of potential exposure to infected ticks, not only in states with high incidence but also in areas where Lyme disease is known to be emerging. These findings underscore the ongoing need to implement personal prevention practices routinely (e.g., application of insect repellent and inspection for and removal of ticks) and to develop other effective interventions.