The first imported case of rabies into Japan in 36 years: a forgotten life-threatening disease

Evaluation of potential rabies exposure among Japanese international travelers: A retrospective descriptive study

BACKGROUND

Although Japan has been a rabies-free country for >50 years, a few cases have been reported among people traveling abroad. This study aimed to investigate animal exposure among Japanese travelers using the Japanese Registry for Infectious Diseases from Abroad (J-RIDA).

METHOD

In this retrospective analysis, we examined Japanese overseas travelers with animal exposure, as included the J-RIDA database, reported from October 1, 2017, to October 31, 2019, with a focus on pre-exposure prophylaxis (PrEP) administration and the animals to which the patients were exposed.

RESULTS

Among the 322 cases included in the analysis, 19 (5.9%) patients received PrEP and 303 did not. The most common purpose of travel was a non-package tour (n = 175, 54.3%). Most trips (n = 213, 66.1%) were to a single country for <2 weeks. Most patients (n = 286, 87.9%) traveled to countries with a rabies risk. The majority of patients with and without PrEP were injured in rabies-risk countries [n = 270 (89.1%) for non-PrEP and n = 16 (84.2%) for PrEP]. Animals associated with injuries included dogs (55.0%), cats (25.5%), and monkeys (15.5%). Most patients were classified as World Health Organization Category II/III for contact with suspected rabid animals (39.5% and 44.1% for categories II and III, respectively) and had exposure within 5 days of travel. Southeast Asia (n = 180, 55.9%) was the most common region in which travelers were exposed to animals.

CONCLUSIONS

Japanese overseas travelers had contact with animals that could possibly transmit the rabies virus, even on short trips. Promoting pre-travel consultation and increasing awareness of the potential for rabies exposure are important for prevention of rabies among Japanese international travelers.

Fourth imported rabies case since the eradication of rabies in Japan in 1957

A 32-year-old man, who visited Japan from the Philippines in 2020, was diagnosed with rabies, the first reported case in Japan since 2006. This is the fourth imported case of rabies since 1957; one case in 1970 was imported from Nepal and two in 2006 were imported from the Philippines.

Travel medicine facilities: The first nationwide cross-sectional questionnaire survey in Japan

INTRODUCTION

Travel medicine has gained importance in recent years; however, there is little data regarding travel medicine departments in Japanese hospitals.

METHODS

This cross-sectional study contacted 488 hospitals designated by either the Japanese government or major Japanese associations. A questionnaire comprising 11 questions pertaining to the availability of pre-travel consultation, out-of-hours service for travel-related patients, number of medical doctors engaged in travel medicine and infectious disease specialists, and the number of negative pressure rooms available for inpatients and outpatients was distributed. It also asked about the facilities available to combat specific diseases like malaria, dengue, and post-exposure prophylaxis for rabies as these are most common diseases affecting returning travelers.

RESULTS

Of the 263 hospitals (58.7%) that responded to our questionnaire, 82 hospitals (31.2%) provided pre-travel consulting, 188 hospitals (72.0%) accepted travel-related patients out-of-hours, median (interquartile range [IQR]) number of medical doctors involved in travel medicine was 1 (0-3), and median (IQR) number of patients accepted for admission was 2 (1-4). Only 106 (41%) hospitals could diagnose malaria at any time, 56 hospitals (21%) could immediately provide oral anti-malarial medicines; rapid diagnostic test for dengue was available in 99 hospitals (39%), while 67 hospitals (26%) could immediately administer post-exposure prophylaxis for rabies.

CONCLUSIONS

Japan's medical care system is concerned about illnesses-especially malaria, dengue and rabies in returned travelers. We suggest construction of a medical care system centered on designated medical facilities for category I and II infectious diseases to build capacity for early diagnosis and treatment of common tropical infectious diseases.

Purified Vero Cell Rabies Vaccine (PVRV, Verorab®): A Systematic Review of Intradermal Use Between 1985 and 2019

The purified Vero cell rabies vaccine (PVRV; Verorab®, Sanofi Pasteur) has been used in rabies prevention since 1985. Evolving rabies vaccination trends, including shorter intradermal (ID) regimens with reduced volume, along with WHO recommendation for ID administration has driven recent ID PVRV regimen assessments. Thus, a consolidated review comparing immunogenicity of PVRV ID regimens during pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) is timely and beneficial in identifying gaps in current research. A search of seven databases for studies published from 1985 to November 2019 identified 35 studies. PrEP was assessed in 10 studies (n = 926) with 1-3-site, 1-3-visit regimens of up to 3-months duration. Seroconversion (rabies virus neutralizing antibodies [RVNA] ≥ 0.5 IU/mL) rates of 90-100% were reported within weeks, irrespective of regimen, with robust booster responses at 1 year (100% seroconversion rates by day 14 post-booster). However, data are lacking for the current WHO-recommended, 2-site, 1-week ID PrEP regimen. PEP was assessed in 25 studies (n = 2136) across regimens of 1-week to 90-day duration. All ID PEP regimens assessed induced ≥ 99% seroconversion rates (except in HIV participants) by day 14-28. This review confirms ID PVRV suitability for rabies prophylaxis and highlights the heterogeneity of use in the field.

Molecular characterization of nucleoprotein gene of rabies virus from Maharashtra, India

Context:

Rabies poses a serious public health concern in developing countries such as India. Aims: The study focuses on molecular diagnosis of street rabies virus (RABV) from human clinical specimens received from Maharashtra, India.

Materials and Methods:

Nucleoprotein gene from eight (of total 20 suspected samples) rabies cases that tested positive for rabies antigen using reverse transcriptase-polymerase chain reaction (RT-PCR) were sequenced.

Results:

Sequence analysis using basic local alignment search tool (BLAST) and multiple sequence alignment (MSA) and phylogenetic analysis showed similarity to previously reported sequences from India and those of Arctic lineages.

Conclusions:

The circulating RABV strains in Maharashtra, India show genetic relatedness to RABV strains reported from Indo-Arctic lineages and India-South and Japan.

Epidemiology, Impact and Control of Rabies in Nepal: A Systematic Review

Background

Rabies is a vaccine-preventable viral zoonosis belonging to the group of neglected tropical diseases. Exposure to a rabid animal may result in a fatal acute encephalitis if effective post-exposure prophylaxis is not provided. Rabies occurs worldwide, but its burden is disproportionately high in developing countries, including Nepal. We aimed to summarize current knowledge on the epidemiology, impact and control of rabies in Nepal.

Methods

We performed a systematic review of international and national scientific literature and searched grey literature through the World Health Organization Digital Library and the library of the National Zoonoses and Food Hygiene Research Centre, Nepal, and through searching Google and Google Scholar. Further data on animal and human rabies were obtained from the relevant Nepalese government agencies. Finally, we surveyed the archives of a Nepalese daily to obtain qualitative information on rabies in Nepal.

Findings

So far, only little original research has been conducted on the epidemiology and impact of rabies in Nepal. Per year, rabies is reported to kill about 100 livestock and 10–100 humans, while about 1,000 livestock and 35,000 humans are reported to receive rabies post-exposure prophylaxis. However, these estimates are very likely to be serious underestimations of the true rabies burden. Significant progress has been made in the production of cell culture-based anti-rabies vaccine and rabies immunoglobulin, but availability and supply remain a matter of concern, especially in remote areas. Different state and non-state actors have initiated rabies control activities over the years, but efforts typically remained focalized, of short duration and not harmonized. Communication and coordination between veterinary and human health authorities is limited at present, further complicating rabies control in Nepal. Important research gaps include the reporting biases for both human and animal rabies, the ecology of stray dog populations and the true contribution of the sylvatic cycle.

Interpretation

Better data are needed to unravel the true burden of animal and human rabies. More collaboration, both within the country and within the region, is needed to control rabies. To achieve these goals, high level political commitment is essential. We therefore propose to make rabies the model zoonosis for successful control in Nepal.

Rabies has been known as a deadly disease in Nepal for decades, but information on epidemiology, impact and control remains scattered. We collected and summarized information from a variety of sources, including scientific literature and government agencies. Only little original research has been conducted on the epidemiology and impact of rabies in Nepal, leaving many questions unanswered. Official reports show that each year 100 livestock and 10–100 humans die of rabies, but these numbers very likely underestimate the true rabies burden. Availability and supply of anti-rabies vaccines have remained suboptimal and rabies control activities have been hampered by a lack of collaboration and comprehensiveness. High level political commitment is essential to overcome these problems and to reduce the burden of rabies. We therefore propose to make rabies the model zoonosis for successful control in Nepal.

Post-Travel Consultations in a Regional Hub City Hospital, Japan

OBJECTIVE

To clarify the characteristics of post-travel consultation services in Japan, particularly in the provinces, we analyzed our post-travel patients in the travel clinic of Kurume University Hospital located in Kurume City (a regional hub City in southwestern Japan).

METHODS

Sixty post-travel patients visited our clinic between April 2008 and October 2014 and participated in this study: 55 were Japanese and five were foreign. We summarized and compared the characteristics of the patients after dividing the Japanese participants into long-term travelers (>14 days) and short-term travelers (≤14 days). The foreign travelers were described in a separate analysis.

RESULTS

Of the 55 Japanese travelers, the mean age (± standard deviation) was 37.3 ± 16.3 years, and 36 patients (65%) were men. Southeast Asia was the major destination (30/55, 55%), and business was stated as the major reason for travel (16/55, 29%). Post-exposure rabies prophylaxis (16/55, 29%) was the most common purpose for the consultations. There were 34 participants (62%) who were classified as short-term travelers. Fewer of the short-term travelers stated receiving pre-travel consultations compared with long-term travelers (11% vs. 79%, p=0.0002). The five foreign travelers included one dengue fever patient and two malaria patients.

CONCLUSION

Most post-travel Japanese patients visited our clinic were short-term travelers who had not received any pre-travel consultation. One of the most common complaints, post-exposure rabies prophylaxis, could have been avoided to some extent by appropriate pre-travel consultations. The results of this study suggest that pre-travel consultations should therefore be encouraged for both long- and short-term travelers.

Association between RABV G Proteins Transported from the Perinuclear Space to the Cell Surface Membrane and N-Glycosylation of the Sequon Asn(204)

In this study, G proteins of the rabies virus (RABV) Kyoto strain were detected in the cytoplasm but not distributed at the cell membrane of mouse neuroblastoma (MNA) cells. G proteins of CVS-26 were detected in both the cell membrane and perinuclear space of MNA cells. We found that N-glycosylation of street RABV G protein by the insertion of the sequon Asn(204) induced the transfer of RABV G proteins to the cell surface membrane. Fixed RABV budding from the plasma membrane has been found to depend not only on G protein but also on other structural proteins such as M protein. However, the differing N-glycosylation of G protein could be associated with the distinct budding and antigenic features of RABV in street and fixed viruses. Our study of the association of N-glycan of G protein at Asn(204) with the transport of RABV G protein to the cell surface membrane contributes to the understanding of the evolution of fixed virus from street virus, which in turn would help for determine the mechanism underlying RABV budding and enhanced host immune responses.

Incidence of potential rabies exposure among Japanese expatriates and travelers in Thailand

BACKGROUND

Rabies has become a forgotten and neglected disease in Japan. In 2006, there was a slight increase in social awareness of rabies when Japan had two reported cases of human rabies, originating in the Philippines. Although the number of Japanese either traveling or living in other Asian countries has been increasing, the exact risk of this population contracting rabies is unknown. Thus, this study utilized a questionnaire to investigate the incidence of rabies exposure, as well as the knowledge, attitude, and practice toward rabies prevention among Japanese expatriates and travelers in Thailand.

METHODS

Japanese travelers and expatriates were asked questions related to knowledge, attitude, practice toward rabies risk, and experiences of potential rabies exposure such as animal bites, licks, and scratches. Questionnaires were either completed at the Bangkok Suvarnabhumi International Airport and other tourist areas or distributed within Japanese associations in Thailand.

RESULTS

A total of 1,208 questionnaires from Japanese expatriates and 590 from Japanese travelers were collected and analyzed. We found high incidence rates of potential exposure events among these populations. In particular, Japanese travelers had the highest incidence rate compared to previous studies of international travelers in Thailand. While expatriates' incidence rates of animal bites, licks, and scratches were 1.7, 6.9, and 1.8/1,000 person-months, travelers have much higher incidence rates of 43.1, 136.1, and 33.0/1,000 person-months. Generally, travelers, compared to expatriates, tended to have less accurate knowledge and less often had the pre-exposure prophylaxis vaccination. Moreover, survey answers indicated that 55.0% of expatriates and 88.9% of travelers who were bitten would not seek proper treatment.

CONCLUSIONS

Since rabies is a preventable disease as long as one has the appropriate knowledge, attitude, and practice, it is essential to promote prevention activities for the Japanese population in Thailand to avert serious consequences of this disease.

Epidemiologic features of animal bite cases occurring in rabies-endemic areas of Korea, 2005 to 2009

OBJECTIVES

Human rabies is a reemerging infectious disease in Korea. There was no human rabies case for 14 years until the disease had reoccurred in 1999. To prevent occurrence of human rabies, surveillance for animal bite patients in rabies endemic areas in Korea was conducted since 2005 as a part of a human rabies control program. The animal bite cases were analyzed to determine whether patients were treated according to the post-exposure prophylaxis (PEP) guideline of the Korea Centers for Disease Control and Prevention.

METHODS

Information of animal bite cases that occurred from 2005 to 2009 in rabies high-risk regions were collected by cooperation with Regional Public Health Centers in 18 cities/districts of rabies endemic areas.

RESULTS

A total of 2458 animal bite cases were reported. Dogs accounted for 86% of animal bites and 67% of the animals were not vaccinated against rabies virus. For PEP, among rabies-vaccinated animals, 92.7% were observed for clinical signs and 1.4% underwent necropsy. Among unvaccinated animals, 72.7% were observed for clinical signs and 4.1% underwent necropsy. The remaining animals were not available for examination. Of the animal bite patients, 32.5% received PEP and 51.6% were treated by first aid or by washing the wound.

CONCLUSIONS

Given that no human rabies cases were reported since 2005 and animal rabies was continuously reported in endemic areas of Korea, the human rabies control program implemented in 2005 appears to have a significant role in the prevention and control of human rabies.

Genetic diversity and geographic distribution of genetically distinct rabies viruses in the Philippines

Background

Rabies continues to be a major public health problem in the Philippines, where 200–300 human cases were reported annually between 2001 and 2011. Understanding the phylogeography of rabies viruses is important for establishing a more effective and feasible control strategy.

Methods

We performed a molecular analysis of rabies viruses in the Philippines using rabied animal brain samples. The samples were collected from 11 of 17 regions, which covered three island groups (Luzon, Visayas, and Mindanao). Partial nucleoprotein (N) gene sequencing was performed on 57 samples and complete glycoprotein (G) gene sequencing was performed on 235 samples collected between 2004 and 2010.

Results

The Philippine strains of rabies viruses were included in a distinct phylogenetic cluster, previously named Asian 2b, which appeared to have diverged from the Chinese strain named Asian 2a. The Philippine strains were further divided into three major clades, which were found exclusively in different island groups: clades L, V, and M in Luzon, Visayas, and Mindanao, respectively. Clade L was subdivided into nine subclades (L1–L9) and clade V was subdivided into two subclades (V1 and V2). With a few exceptions, most strains in each subclade were distributed in specific geographic areas. There were also four strains that were divided into two genogroups but were not classified into any of the three major clades, and all four strains were found in the island group of Luzon.

Conclusion

We detected three major clades and two distinct genogroups of rabies viruses in the Philippines. Our data suggest that viruses of each clade and subclade evolved independently in each area without frequent introduction into other areas. An important implication of these data is that geographically targeted dog vaccination using the island group approach may effectively control rabies in the Philippines.

Rabies continues to be a major public health problem in the Philippines. We conducted a molecular epidemiological study of rabies using the complete glycoprotein (G) gene from 235 animal brain samples collected in the Philippines between 2004 and 2010. We identified three major clades and two distinct genogroups in the Philippines. The three major clades L, V, and M were found specifically in the Luzon, Visayas, and Mindanao island groups, respectively. Additionally, two minor genogroups were located in the Luzon island group. These data suggest that although human mediated transmission may have occurred, these virus clades evolved independently after a single introduction into each island group. All of the analyzed Philippine strains were clustered into Asian 2b, which diverged from the Chinese strain Asian 2a. No recent introduction of rabies into the Philippines from other countries was apparent. The elimination of rabies by 2020 is a national goal in the Philippines, necessitating urgent development of a more effective and feasible strategy for controlling rabies. Our findings indicate that a geographically targeted dog vaccination campaign may effectively control rabies in island nations such as the Philippines.

Communicable Diseases After the Disasters: with the Special Reference to the Great East Japan Earthquake

On March 11, 2011, the Great East Japan Earthquake – a massive temblor followed by a gigantic tsunami was associated with significant morbidity and mortality. Among many health problems such as trauma, drowning, and mental illnesses, infectious diseases may place significant burden on survivors of such disasters. Wound infections including tetanus, leptospirosis, legionellosis, rickettsiosis, respiratory infections, and diarrheal illness among other infections had been considered to be associated with earthquake and tsunami. Overall, the impact of infectious diseases after the Great East Japan Earthquake was relatively small, with only sporadic outbreaks observed. The incidence of serious infections such as tetanus, legionellosis, and tsunami lung, was also low, considering the overall impact of the earthquake and tsunamiper se. This review discusses the impact of infectious diseases after the Great East Japan Earthquake, and reviews past disaster-related infections as reference.

From brain passage to cell adaptation: the road of human rabies vaccine development

A major challenge for global rabies prevention and control is the lack of sufficient and affordable high quality vaccines. Such candidates should be pure, potent, safe, effective and economical to produce, with broad cross-reactivity against viral variants of public health and veterinary importance. The history of licensed human vaccines reviewed herein demonstrates clearly how the field has evolved to the current state of more passive development and postexposure management. Modern cell culture techniques provide adequate viral substrates for production of representative verified virus seeds. In contrast to outdated nervous tissue-based rabies vaccines, once a suitable substrate is identified, production of high titer virus results in a major qualitative and quantitative difference. Given the current scenario of only inactivated vaccines for humans, highly cell-adapted and stable, attenuated rabies viruses are ideal candidates for consideration to meet the need for seed viruses in the future.

Rabies vaccination for international travelers

Rabies prevention in travelers is a controversial issue. According to experts, the decision to vaccinate results from an individual risk assessment based on the duration of stay, the likelihood of engagement in at-risk activities, the age of the traveler, the rabies endemicity and access to appropriate medical care in the country of destination. However, no detailed information is available regarding the last two determinants in many regions. Twenty-two cases of rabies were reported in tourists, expatriates and migrant travelers over the last decade, including three cases following short-term travel of no more than two weeks. Studies on rabies post-exposure prophylaxis (PEP) in travelers show that overall, 0.4% (range 0.01-2.3%) of travelers have experienced an at-risk bite per month of stay in a rabies-endemic country, while 31% of expatriates and 12% of tourists were vaccinated against rabies before traveling. The main reason cited by travelers for not being vaccinated is the cost of the vaccine. The majority of patients who sustained a high risk injury was not vaccinated against rabies before traveling and were not properly treated abroad. From available studies, the following risk factors for injuries sustained from potentially rabid animals may be identified: traveling to South-East Asia, India or North Africa, young age, and traveling for tourism. The duration of travel does not appear to be a risk factor. It should be noted that "at-risk activities" have not been addressed in these studies. Detailed rabies distribution maps and information on the availability of rabies biologics are urgently needed in order to identify those travelers who need pre-travel vaccination. Meanwhile, cost-minimization of rabies pre-exposure vaccination may be achieved in several ways, notably by using the intra-dermal method of vaccination.

Pre-exposure immunization against rabies using Japanese rabies vaccine following the WHO recommended schedule

We examined the efficacy and safety of the Japanese purified chick embryo cell rabies vaccine (PCEC-K) when administered on days 0, 7, and 28, as recommended by the WHO. Post-vaccination serum samples were obtained from 53 human subjects, and rabies antibody titers were determined by a combination of enzyme-linked immunosorbent assay (ELISA) and neutralizing antibody (NA) assay. By day 42 of the experiment, which was 2 weeks after the third dose, all subjects had developed NA titers of 0.5 IU/ml or higher. The geometric mean titers of ELISA antibody and NA were 3.8 EU/ml and 5.7 IU/ml, respectively. Overall, the vaccine was well tolerated by all subjects. These results suggest that PCEC-K used for pre-exposure immunization according to the WHO schedule is as immunogenic and effective as the current pre-exposure immunization regimen in Japan, which consists of vaccines administered on days 0, 28, and 180. An accelerated schedule would be of great advantage to Japanese travelers, who could complete the required three doses for primary immunization in 1 month.

Knowledge, attitudes, and practices of Japanese travelers on infectious disease risks and immunization uptake

BACKGROUND

There is concern that Japanese travelers are poorly protected against travel-associated infectious diseases including vaccine-preventable infections. This prompted us to study Japanese travelers for measures taken to reduce their risk of acquiring an infectious disease and their immunization uptake.

METHODS

During April 2007 to May 2008, a questionnaire study was conducted using the European Travel Health Advisory Board (ETHAB) protocol and targeting Japanese group tour clients as well as individual travelers to developing countries.

RESULTS

A total of 302 returned questionnaires were analyzed. While the majority (87.4%) sought general information on their destination, few (38.7%) sought the travel health information. Very few (2.0%) got the health information from travel medicine specialists. More than half were either unaware of the risks or thought there was no risk of hepatitis A, hepatitis B, and typhoid fever in their destination. Only half (50.7%) thought vaccines provided sufficient protection and very few (13.6%) believed that vaccines were safe. For most of the vaccine-preventable diseases, only fewer than 10% had received the vaccines.

CONCLUSIONS

There is a need for specialized travel health services in Japan and health professionals should be encouraged to expand these services. Japanese travelers should be made aware of the importance of seeking pre-travel health advice and information on the health risks at their destination. Travel health professionals should provide a balanced view of the risks and benefits of immunization, and misperceptions about immunization should be addressed.