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Background Nosocomial (hospital-acquired) influenza A virus infection is a very important clinical issue. The objective of this study is to describe the effect of baloxavir marboxil in controlling an outbreak of this infection. Methods A retrospective observational study was performed to assess the effectiveness of baloxavir marboxil in the treatment of nosocomial infections caused by oseltamivir-resistant influenza virus A. Results In September 2019, there was an outbreak of nosocomial influenza A(H1N1)pdm09 viral infection in one out of three facility wards for inpatients at the Okinawa Nanbu Regional Center for Children with Special Needs. Symptomatic staff members were kept off duty until they remained afebrile for 2 days. Prophylactic oseltamivir was administered to inpatients (n = 37) and to staff members (n = 16) who voluntarily requested the drug. However, both inpatients and staff members showed influenza A infection during prophylactic use of oseltamivir. The A(H1N1)pdm09 virus sample obtained from one patient was shown to be oseltamivir-resistant. After administration of baloxavir marboxil, the nosocomial outbreak gradually ceased. Moreover, the time (hours) to alleviation of fever in the oseltamivir group (n = 11) and baloxavir marboxil group (n = 13) was significantly different (p = 0.0034). Conclusion Our report provides evidence for the usefulness of baloxavir marboxil in treating influenza A patients who have received prophylactic doses of oseltamivir. This is the first report describing the successful use of baloxavir marboxil for of a nosocomial outbreak caused by oseltamivir-resistant influenza A virus.

In this paper we report two incidents of ciguatera fish poisoning (CFP) that occurred in 2008 on Kakeroma Island in Kagoshima Prefecture, Japan. A family consisting of father (42 y.o.), mother (39 y.o.), daughter (11 y.o.) and son (6 y.o.), as well as a friend of the family (male, 78 y.o.) consumed sliced flesh (sashimi) and developed typical symptoms of CPF 4-5 h later: diarrhea, vomiting, and paresthesia of the extremities. Additionally, the two male adults (42 and 78 y.o.) developed mild hypotention (84/48 and 94/40 mmHg, respectively) and bradycardia (36 and 50 bpm, respectively) and were rushed to the ER of the nearest hospital, located on an adjacent island. The implicated fish were caught together off the west coast of the island and were identified as Variola louti and Lutjanus monostigma based on analysis of 16S rRNA gene coded on mtDNA. Remnants of the implicated fish and other fish caught on the same occasion were examined by the official mouse bioassay method (MBA), which defines the minimum amount of CFP toxin needed to kill a male mouse of ddY strain of 20 g body weight within 24 h as one mouse unit (MU). A significantly high toxicity was detected in the V. louti (0.2 MU/g) eaten by the family and the L. monostigma (0.8 MU/g) eaten by the elderly man. Other specimens of Lethrinus nebulosus, Variola albimarginata, Lutjanus gibbus (2 specimens), Aphareus rutilans, and Sphyraena forsteri (2 specimens) were found to be nontoxic (< 0.025 MU/g). The medical records regarding island inhabitants (ca. 1,500) kept at Kakeroma Tokushukai Clinic, the only medical facility on the Island, and also at Setouchi Tokushukai Hospital, a nearest hospital on an adjacent island (Amami) revealed 6 CFP outbreaks involving 13 cases between 2005 and 2008. The estimated frequency of CFP was 10.0 incidents/10,000 persons/year and the morbidity rate was 21.7 cases/10,000 persons/year. The symptoms and signs observed in the patients and the implicated fish species, L. monostigma and V. louti, were typical of CFP in this region.

A husband and wife successively visited an emergency room with symptoms of staggering, slurred speech, mydriasis, and drowsiness, three hours after separately eating spaghetti with meat sauce. The sauce contained eggplant that had been grafted onto a Devil's trumpet, Datura metel. Scopolamine and atropine were detected in the leftover sauce and in the sera of the patients. This is the first case of food poisoning related to Datura in Okinawa, Japan and also might be the first report of food poisoning caused by intake of a vegetable grafted onto Datura in Japan.

Toxin profiles of representative ciguatera species caught at different locations of Japan were investigated in fish flesh by high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. Identification and quantification of 16 toxins were facilitated by the use of 14 reference toxins prepared by either synthesis or isolation from natural sources and the previous LC-MS data thereof. Sodium adduct ions [M + Na](+) were used as parent and product ions. Distinct regional differences were unveiled: ciguatoxin-1B type toxins were found in snappers and groupers from Okinawa, ciguatoxin-3C type toxins were found in a spotted knifejaw, Oplegnathus punctatus, from Miyazaki located 730 km north of Okinawa, and both types of toxins were found in a red snapper, Lutjanus bohar, from Minamitorishima (Marcus) Island. Twelve toxins were identified in a dinoflagellate, Gambierdiscus toxicus, collected as the primary toxin source in French Polynesia. Occurrence of M-seco-toxins in fish and oxidized toxins in the dinoflagellate was confirmed for the first time. The present LC-MS/MS method is rapid, specific, and accurate. It not only outperforms the currently employed mouse bioassays but also enables the study of the toxin dynamics during the food chain transmission.

Okinawa being located in the subtropical region has the highest incidence of ciguatera in Japan. Officially, 33 outbreaks involving 103 patients have been reported between 1997 and 2006. The implicated species were Variola louti, Lutjanus bohar, Lutjanus monostigma, Epinephelus fuscoguttatus, unidentified Lutjanus sp., Plectropomus areolatus, Oplegnathus punctatus, Epinephelus polyphekadion, Caranx ignobilis and moray eel. Toxicities of the leftover meals, as determined by mouse bioassays, ranged from 0.025 to 0.8 MU/g or above (equivalent to 0.175–5.6 ng CTX1B/g). We collected 612 specimens of fish belonging to L. monostigma, L. bohar, Lutjanus argentimaculatus, Lutjanus russellii, V. louti, Variola albimarginata, and E. fuscoguttatus from the coasts around Okinawa and examined the toxicity of the flesh by the mouse bioassay. The rate of toxic fish was as follows: L. monostigma: 32.3%, L. bohar: 11.9%, V. louti: 14.3%, E. fuscoguttatus: 20.8%. Only one out of 36 samples of V. albimarginata and two of 74 samples of L. russellii were found toxic. None of the 35 samples of L. argentimaculatus was toxic. Nor the L. bohar samples weighing less than 4 kg were toxic. In all toxic samples, CTX1B was detected by LC/MS analysis but CTX3C and 51-hydroxyCTX3C were not.