Participants take part in the comprehensive epidemic prevention and control drills during the "Peace Train-2019" China-Laos humanitarian and medical joint rescue exercise in Vientiane, capital of Laos, Aug. 18, 2019. (Xinhua/Zhang Jianhua)

The Chinese People's Liberation Army (PLA)'s Z-8G rescue helicopter participates in the "Peace Train-2019" China-Laos humanitarian and medical joint rescue exercise in the northern suburbs of Lao capital Vientiane, Aug. 18, 2019. It is the first time for the Chinese helicopter to fly abroad to attend a joint health and logistic drill. (Xinhua/Xiong Tianze)

Participants take part in the comprehensive epidemic prevention and control drills during the "Peace Train-2019" China-Laos humanitarian and medical joint rescue exercise in Vientiane, capital of Laos, Aug. 18, 2019. (Peace Train medical team/Handout via Xinhua)

Participants take part in the comprehensive epidemic prevention and control drills during the "Peace Train-2019" China-Laos humanitarian and medical joint rescue exercise in Vientiane, capital of Laos, Aug. 18, 2019. (Peace Train medical team/Handout via Xinhua)

Participants take part in the comprehensive epidemic prevention and control drills during the "Peace Train-2019" China-Laos humanitarian and medical joint rescue exercise in Vientiane, capital of Laos, Aug. 18, 2019. (Peace Train medical team/Handout via Xinhua)

Participants take part in the comprehensive epidemic prevention and control drills during the "Peace Train-2019" China-Laos humanitarian and medical joint rescue exercise in Vientiane, capital of Laos, Aug. 18, 2019. (Peace Train medical team/Handout via Xinhua)