In recent years, avian influenza due to highly pathogenic avian influenza virus A/H5N1 (hereafter will be abbreviated to H5N1) has spread among birds from Asia (see p. 185 of this issue) to Europe and Africa. Moreover, the infection from birds to humans occurred in Southeast Asia (385 cases in 15 countries as of June 19, 2008) (see p. 183 of this issue). Misgivings about global pandemic influenza have arisen from the potency of H5N1 acquiring the ability to cause human-to-human infection by viral mutation. On the basis of such situation, to minimize the damage if an influenza pandemic occurs, the revision of the laws was required to conduct the indispensable countermeasures promptly and certainly before and after the outbreak, and the Infectious Diseases Control Law and the Quarantine Law were revised at this time.
In this article, addition to the outlines of principal revisions of the Infectious Diseases Control Law and the Quarantine Law, enhanced measles control measures operating from this year in compliance with the Infectious Diseases Control Law and the Preventive Vaccination Law are described.
<Infectious Diseases Control Law>
1. Revision of classification of targeted diseases
The government ordinance enacted on June 12, 2006, designating influenza (H5N1) as a specially designated infectious disease, was abolished. Avian influenza virus (H5N1) infection was added to the category II infectious diseases and a new category of pandemic influenza and relevant infections, consisting of pandemic influenza and re-emerging pandemic influenza, was created to prepare for the occurrence of influenza pandemic (Table 1).
(1) Addition of a new category, pandemic influenza and relevant infections: Because the nationwide rapid spread of pandemic influenza or re-emerging pandemic influenza will give serious impact on lives and health of the people, such response exceeding conventional measures for infectious disease control is needed. However, full response can not be made if these two diseases were ranked in one of the pre-existing categories I-V, so a new category was created.
Pandemic influenza is defined as influenza due to the virus newly acquiring an ability to transmit from human-to-human and recognized to give serious impact on lives and health of the people by nationwide rapid spread because the people generally have no immunity and re-emerging pandemic influenza as influenza once broke out on worldwide level like Asian flu (H2N2) but long time passed without causing epidemic, prescribed by the Minister of Health, Labour and Welfare, and re-emerged as giving serious impact on lives and health of the people by a nationwide rapid spread because most people have generally no immunity.
In addition, suspected cases and asymptomatic carriers of pandemic influenza and relevant infections are regarded as patients, on which the laws are applicable.
(2) Re-categorization of other types of influenza, accompanying creation of pandemic influenza and relevant infections: Avian influenza virus (H5N1) infection is a serious disease with a high case-fatality rate through bird-to-human infection and is supposed to have a possibility of mutation to human influenza virus which transmits from human-to-human. In addition, from the fact that restrictive human-to-human infections in family incidents have been reported at the present time, avian influenza virus (H5N1) infection is classified into category II, applicable to hospitalization of cases and suspected cases depending upon the conditions to prevent infection to other people.
It has been expressed that avian influenza virus (H5N1) infection is excluded from avian influenza virus infection in the category IV and that avian influenza virus infection (H5N1 and others), pandemic influenza and relevant infections are excluded from influenza in the category V.
(3) Definition of pathogen classification: The pathogens of pandemic influenza and relevant infections are considered to be on the same level as H5N1 and H2N2 in the pathogenicity to humans and the influence upon lives and health of the people. Therefore, they have been classified into the same group 4 as H5N1 and H2N2, and the regulatory rules for handling facility and storage standards are applied (http://www.mhlw.go.jp/bunya/kenkou/kekkaku-kansenshou17/03.html).
2. Control measures for pandemic influenza and relevant infections
(1) Addition of pandemic influenza and relevant infections to the existing control measures: The control measures in force under the current Infectious Diseases Control Law allowed to be executed for preventive measures against an influenza pandemic are also applicable to pandemic influenza and relevant infections. Such measures that the necessity is not recognized from the present scientific knowledge will be able to apply correspondingly by establishing a government ordinance if necessary after a pandemic has occurred. Because correspondingly applicable measures include prohibition of entering buildings, containment of building or traffic restriction that may infringe the human rights, a government ordinance must be established after consultation with the Section of Infectious Diseases, Health Sciences Council of the Ministry of Health, Labour and Welfare.
(2) New regulations concerning pandemic influenza and relevant infections: In addition, because pandemic influenza and relevant infections are supposed to be highly infectious and it is crucial that operation of preventive measures will be necessary just after occurrence of pandemic, such regulations as enhancement of coordination of governors of prefectures and quarantine stations, publication of information on occurrence and countermeasures, request for reporting about health status of a person having just enough reasons for suspecting infection, request for cooperation of forbearing to go out, and progress reports of countermeasures carried out by local governments concerned are created.
3. New regulations concerning new infectious diseases
Because a new infectious disease is a disease with serious symptoms and with unknown etiology at the time of emergence, control measures similar to those against pandemic influenza and relevant infections will be necessary. Therefore, if occurrence of a new infectious disease is recognized, the government must quickly announce the prevailing area and then its symptoms, laboratory methods to detect the pathogen, diagnosis and treatment, prevention of infection, control measures to be done, and other information necessary for prevention of occurrence or protection of its spread, one by one. Also, the government will request for reporting about health status and for cooperation of forbearing to go out, to a person who has a just enough reason for suspecting infection.
1. Definition of pandemic influenza and relevant infections in quarantine infectious diseases
As the first step of control measures to prevent the spread of pandemic influenza, the shoreline operations are considered to be very important (see p. 182 of this issue). For this reason, pandemic influenza and relevant infections are classified into quarantine infectious diseases, to which mandatory isolation of patients, quarantine of contact cases or other countermeasures are executable. Suspected cases of pandemic influenza and relevant infections are also regarded as patients and the Quarantine Law may be applicable to them.
2. The place of isolation and detainment for cases of pandemic influenza and relevant infections
Because it is necessary for cases of pandemic influenza and relevant infections that specialists of infectious diseases to treat them at the hospitals equipped with facilities to protect infection, special infectious disease hospitals, class 1 and 2 infectious disease hospitals, where the patients who need hospitalization are also admitted under the Infectious Diseases Control Law, are assigned for the place of isolation.
On the other hand, because the assumed number of objects to be quarantined is huge from the supposed strength of infectivity of pandemic influenza and medical resources are limited and to be used for already diseased persons requiring them, facilities for detainment are not limited to medical institutions and it is possible to use hotels, where private rooms are equipped, protective measures for spread of the disease could be taken even if a person develops disease, and the director of a quarantine station approves of using such lodgings or ships as the place for detainment.
3. Observation of health
The director of a quarantine station must notify the suspected case of infection with pandemic influenza or relevant infections to the governor of the metropolis or the prefecture concerned at the time of recognition. Quick response is possible when a case develops the disease under observation by the governor.
<Enhancement of control measures toward measles elimination>
Toward elimination of measles from Japan by 2012 (IASR 28: 239-240, 2007), The special infectious disease prevention guidelines on measles were notified in December 2007 and measles and rubella, the category V infectious diseases under the National Epidemiological Surveillance of Infectious Diseases, were shifted from reporting from sentinel clinics and hospitals to mandatory notification of all cases by physicians within 7 days after diagnosis (if possible, within 24 hours) from January 1, 2008.
At present, measles cases include not only laboratory confirmed but also clinically diagnosed, and rubella cases include also clinically diagnosed (for the criteria for reporting, see http://www.mhlw.go.jp/bunya/kenkou/kekkaku-kansenshou11/01.html).
In addition, second routine immunization of those aged 12-13 years (the first grade students of junior high school) and those aged 17-18 years (including third grade students of high school) with principally measles-rubella vaccine have been started from April 1, 2008 as a temporary measure for a period of five years under the Preventive Vaccination Law. Immunization of more than 95% of each targeted population, first dose at 12 months, second dose at 5-6 years (pre-school), at 12-13 years or at 17-18 years, is the aim (see p. 189 of this issue).