IASR

ISSN 0915-5813

Vol. 41 No. 2 (No. 480) February 2020
Infectious Agents Surveillance Reporthttps://www.niid.go.jp/niid/en/iasr-e.html

Clinical differentiation and symptoms of acute flaccid paralysis(AFP) ..................................................................................................... 19
Japan’s efforts to advance global polio eradication strategy,
including GAPIII .................................................................................. 20
World polio eradication program status and infectious agentssurveillance system .............................................................................. 21
Summary of AFP cases notified to the National Epidemiological
Surveillance of Infectious Diseases (NESID) system ......................... 23
Pathology of AFP due to enterovirus infection ...................................... 25
Current practices and challenges of AFP pathogen testing at
prefectural and municipal public health institutes (PHIs) ............... 27

National Institute of Infectious Diseases andTuberculosis and Infectious Diseases
Control Division,
Ministry of Health, Labour and Welfare

Non-polio enterovirus testing including EV-D68 and EV-A71 inpatients with AFP ................................................................................ 28“Adequate preparations” and “field cooperation” are essential topathogen diagnosis of AFP − examination of EV-D68-related AFM
case diagnosed in non-endemic period in 2017................................... 29
Summary and measures for influenza outbreak at Naha City
Hospital, Okinawa Prefecture, August-September 2019 ................... 30
Treatment of pregnant woman syphilis ................................................. 32
Molecular identification of gastric parasites in Anisakis foodpoisoning cases, Toyama Prefecture, January-June 2018 .................. 34<THE TOPIC OF THIS MONTH>
Acute Flaccid Paralysis in Japan as of December 2019
Acute flaccid paralysis (AFP) is medically a broad term for disorders presenting with acute flaccid motor paralysis of theextremities (see p. 19 of this issue). AFP develops when the anterior horn cells of the spinal cord, along with the peripheral nerves
or muscles, are damaged. Typical diseases causing AFP include Guillain-Barré syndrome (GBS), acute poliomyelitis (polio), andacute flaccid myelitis (AFM).
Global Polio Eradication Initiative and AFP Surveillance: The World Health Organization (WHO) is promoting the
Global Polio Eradication Initiative to terminate the spread of wild-type polioviruses from all countries and regions worldwide (seepp. 20 and 21 of this issue). Although the global eradication of wild-type poliovirus type 2 was declared in September 2015 and type
3 in October 2019, cases of AFP due to vaccine-derived polioviruses (VDPV) have been reported in a broad area of Africa. In theWHO Western Pacific Region (WPR), which includes Japan, outbreaks due to VDPV have also recently occurred in countries such
as Laos, Papua New Guinea, and the Philippines. From the perspective of countermeasures against polio, the WHO has beenmonitoring AFP cases in patients under the age of 15 in each country and has established a system for AFP pathogen surveillanceby conducting virological tests (virus isolation from two stool specimens collected at least 24 hours apart) on patients aged under
15 years in many countries to grasp the situation (see p. 20 of this issue).
National Epidemiological Surveillance of Infectious Diseases (NESID): In Japan, the need for early detection of AFM
and collection of epidemiologic information was pointed out due to the high incidence of AFM in the autumn of 2015. In addition,although Japan was the only country in the WPR that did not conduct AFP surveillance, AFP (except for acute poliomyelitis) wasadded to the list of category V notifiable infectious diseases on May 1, 2018. Any physician who diagnoses AFP is required to notify
the jurisdictional public health center within 7 days of the diagnosis. In addition, specimens must be collected for the pathogen test
after the diagnosis to differentiate it from polio and authorities must notify the occurrence as soon as possible without waiting forthe result of the pathogen test. If poliovirus (including vaccine-derived strains) is detected after notification, the notification of“AFP” under category V infectious diseases must be withdrawn and changed to “acute poliomyelitis” as a category II infectious
disease.
Between May 1, 2018 and November 17, 2019, 209 AFP cases were notified. An epidemic curve, excluding 19 patients whose
onset month is unknown, is shown (Fig. 1). The number was high from September to November 2018, with a peak in October 2018.
Based on the frequency of GBS, the WHO estimates the incidence of AFP to be 1 per 100,000 children aged under 15 years andrecommends it as a sensitivity index for AFP surveillance. However, there were only 16 prefectures in 2018 and 8 prefectures in2019 where the number of notifications exceeded 1 per 100,000 children (Fig. 2).
By age, the peak age was 1 year with a median age of 3 years in 2018. In 2019, there was no evident peak and the median age
was 7 years (Fig. 3 in p.18). By gender, 105 male and 104 female children were notified.
The symptoms of 216 AFP cases notified NESID between May 1, 2018 and November 17, 2019 included monoplegia in 52
patients (24%), paraplegia in 90 patients (upper extremity in 23 patients, lower extremity in 67 patients) (42%), triplegia in 15patients (7%), quadriplegia in 42 patients (19%), respiratory muscle paralysis in 17 patients (8%), facial paralysis in 23 patients50

8No. of notified cases

45

740

Acute flaccid paralysis

35Enterovirus D68

30

6525

420

315

2

101

50

4 5 67 8 9 10 11 12 1 22018

3 4 5 6

No. of enterovirus D68 detections

Figure 1. Monthly number of notified acute flaccid paralysis (AFP) cases* andenterovirus D68 detections**, 1 May 2018- 17 November 2019, JapanFigure 2. Number of cases and cases per 100,000 children aged under 15 yearsof acute flaccid paralysis (AFP), by prefecture, 2018 & 2019, Japan0
12〜56〜910〜

0
7 8 9 10 11 Month2019

No. of notified cases
per 100,000 children

No. of notified cases

201800.1〜0.5〜
1.0〜3.0〜

2019

20182019(National Epidemiological Surveillance of Infectious Diseases: as of 2 December 2019)Year*Excluding 19 cases with unknown date of onset(National Epidemiological Surveillance of Infectious Diseases: as of 2 December 2019)**Including 4 cases with multiple detections(Infectious Agents Surveillance System: as of 2 December 2019)1′（ 17′）（Continued on page 18′）

IASR Vol. 41 No. 2（Feb. 2020） 2′（ 18′）
（THE TOPIC OF THIS MONTH-Continued）
Figure 3. Age and gender distribution of notified acute flaccid paralysis(AFP) cases, 1 May 2018- 17 November 2019, Japan

No. notified cases

30

2018

25

Female

20

Male

15
10
50

No. notified cases

012345678915

10 11 12 13 14 Age2019

10FemaleMale

500

12345678910 11 12 13 14 Age(National Epidemiological Surveillance of Infectious Diseases: as of 2 December 2019)

Table. Type of pathogen reported to the Infectious Agents Surveillance System asacute flaccid paralysis (AFP) cases, 1 May 2018- 17 November 2019
Pathogen detectedEnterovirus NT

Positive sample (isolation/detection)*
No. ofSputum/Cerebrospinal
Throatdetections Stool tracheal
Urine Other
Blood
fluid
swab
aspirate1(1)1-Coxsackievirus A2

11------

Coxsackievirus A4

32-

-

11-

-

Coxsackievirus A511------

Coxsackievirus A63(1)

3-

1-

1--

Coxsackievirus A9

11------

Coxsackievirus A1011------

Coxsackievirus A163(1)

3-

31111

Coxsackievirus B41(1)1------

Echovirus 1122-

21-

-

-

Echovirus 30

1(1)

1-

1-

--

-

Enterovirus D6813(4)

4110-

1-

-

Parechovirus NT1(1)1------

Parechovirus 12(1)2------

Parechovirus 32(2)

2-

11--

115(6)
215(11%), and bladder and rectal disturbance in 37 patients Rhinovirus
2(2)21(17%). No pupillary dilatation suggestive of botulism was Adenovirus 2Adenovirus 511
11
reported (see p. 23 of this issue).
Cytomegalovirus
6(4)
3
1
1
4
Acute Flaccid Myelitis (AFM): AFM was frequent Human herpes virus 6 6(3)151
15in North America during the 2014 epidemic season of Human herpes virus 7 6(3)4(2)
31enterovirus D68 (EV-D68) and in Japan during the 2015 Epstein-Barr virusParvovirus B191(1)111EV-D68 epidemic (see p. 19 of this issue). Symptoms including Total77(34)
32
252
9652
pyrexia and respiratory manifestations developed first, and ( ): Multiple detections NT: Not typed
cases where the same pathogen was detected in different specimens
paralysis frequently exhibited bilaterally asymmetry. T2- *Includes(Infectious Agents Surveillance System: as of 2 December 2019)weighted magnetic resonance imaging (MRI) demonstrated thecharacteristics of long-sized longitudinal lesions predominantly of the gray matter, with high signal intensity and contrast effects on
the cauda equina. Electrophysiological examination revealed motor neuropathy and a mild increase in white blood cell count,predominantly by mononuclear cells, that peaked within 5 days after the onset of paralysis was observed on the cerebrospinal fluid
test (see p. 19 of this issue).
Although the relationship between EV-D68 infection and the development of central nervous system disease in humans isunclear, at the animal experimental level, when respiratory disease-derived EV-D68 was inoculated intracerebrally into neonatal
mice, flaccid paralysis developed from the front limbs and viral antigens were observed in large neurons in the anterior horn of thecervical spinal cord. After inflammation, loss of large neurons and replacement with astroglia were observed, suggesting that theinfection pathology is similar to that of polio (see p. 25 of this issue).
Pathogen Test in AFP Cases: Pathogens detected in AFP cases reported to NESID between May 1, 2018 and November 17,
2019 are listed (Table). Pathogens were most commonly detected from throat swabs, followed by stool. Although the items ofpathogen tests differed depending on the prefectural and municipal public health institutes (PHIs), approximately half of the PHIs
conducted pathogen tests. When other PHIs, the National Institute of Infectious Diseases (NIID), and PHIs that commissioned
universities to conduct the tests were included, pathogen tests were performed for all AFP cases that were notified (see p. 27 of thisissue). Polioviruses were not detected and the peak of AFP notification coincided with the peak of EV-D68 detection (Fig. 1 in p.17).
Polio was only able to be excluded based on the WHO criteria in 7% of the cases of AFP that were notified to the NESID, andthere were many cases in which it was unknown whether a test for poliovirus was performed or in which specimen collection wasinappropriate (see p. 23 of this issue). In the AFP notification form, it is necessary to include a column for the results of poliovirus
tests and the types of specimens tested.
In April 2018, the Health and Labour Sciences Research Group created “Guidelines on Surveillance, Diagnosis, Examination,and Treatment of Diseases with AFP” concerning the detection of AFP and notification of all cases to public health centers fornotifiable disease surveillance, the importance of securing specimens in the acute phase, the laboratory procedures, in addition to
the diagnosis, examination, and treatment of AFM cases. Detection of EV-D68 from the cerebrospinal fluid is difficult, and theviruses are most frequently obtained from specimens of respiratory origin in the acute phase. Polioviruses and enterovirus A71 areneurotropic viruses, but their detection from cerebrospinal fluid is difficult. The viruses are most frequently obtained from stoolspecimens (see p. 28 of this issue). For the diagnosis of AFP pathogens, it is important to secure specimens, such as throat swabs,stools (it is required to collect two separate specimens), blood, and cerebrospinal fluid, in the acute phase, and prior preparation andcooperation in the field are essential (see p. 29 of this issue).
Future Measures: AFP surveillance began in Japan in May 2018. However, as of 2019, the number of cases reported has notreached one or more per 100,000 children, which is recommended as a sensitivity index of surveillance. In addition, under theGlobal Polio Eradication Initiative, it is required that two stool specimens collected at least 24 hours apart within 14 days from theonset of paralysis be tested for poliovirus. To confirm the maintenance of poliovirus eradication and detect AFP pathogens,cooperation among medical institutions, public health centers, PHIs, and NIID is indispensable.

The statistics in this report are based on 1) the data concerning patients and laboratory findings obtained by the National Epidemiological
Surveillance of Infectious Diseases undertaken in compliance with the Act on the Prevention of Infectious Diseases and Medical Care for Patientswith Infectious Diseases, and 2) other data covering various aspects of infectious diseases. The prefectural and municipal health centers andpublic health institutes (PHIs), the Department of Environmental Health and Food Safety, the Ministry of Health, Labour and Welfare, andquarantine stations, have provided the above data.

Infectious Disease Surveillance Center, National Institute of Infectious Diseases
Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, JAPAN Tel (+81-3)5285-1111