Villagers looking at a new mosquito net to fight malaria in their village, Matongo, Zambia. Photo: CFP

Wang Mei (pseudonym) traveled to Kenya in Africa in the summer of 2013. One month after the journey, the woman in her 50s who lives in Jilin Province noticed she suffered continuous fever. The local hospital could not give her effective treatment.

The number of platelets in her blood plummeted. A blood transfusion helped ease some symptoms but failed to stop the fever. Because of her travels to Africa, she was referred to the Tropical Medicine Research Institute at the Beijing Friendship Hospital, where she was finally given the correct diagnosis: malaria.

"When I learned her recent travel history I suspected it was malaria," said Zou Yang, a senior doctor at the hospital. "And then we were able to confirm the diagnosis by the microscopic examination of blood, indicating the existence of parasitic protozoans."

Malaria is an infectious disease spread by bites from mosquitoes. The mosquitoes transmit parasites to the human body. The parasites then settle in the liver to mature and reproduce. Usually, symptoms appear after a period of seven days or longer. At first, typical symptoms include fever, headache and chills. If not treated on time, the disease can progress to coma and, in some cases, death.

Wang is not alone in coming back with an exotic disease from overseas travels. The past few years have witnessed an increase of malaria cases in China amid a massive surge in international travel for trade, work and tourism. According to the website of the World Health Organization (WHO), "International travelers could be at risk of malaria infection in 99 countries around the world, mostly in Africa, Asia and the Americas."

Apart from malaria, other insect-borne diseases such as dengue, leishmaniasis and Lyme disease have been detected in international travelers who return to China.

"Some of the symptoms can take days or weeks to develop after travels. This may lead to delays in making the correct diagnosis and increase the difficulties in rescuing patients," said Zou.

Mosquitos previously stayed away from air conditioned rooms, but are starting to adapt and ignore the cold in search of human blood. Photo:IC

Unwelcome visitor

Spaniard Karim Nimri, a 40-year-old traditional Chinese medicine practitioner, has suffered twice from insect-borne diseases. Nimri, who now lives in Beijing running a website introducing Chinese travel destinations to foreigners, says he was almost killed by malaria 15 years ago when he was in India.

At the age of 25, Nimri travelled to Varanasi in India and stayed in the city to learn a traditional Indian instrument from local musicians. One evening after he made a phone call to his family members in Spain, the disease awakened in his body.

"It started from feeling a headache. Then I decided to go to bed to sleep. The next day, I felt very bad, dizzy and had a strong fever. My digestive system stopped working and I could not eat anything at all," he recalled. 

At first, he thought it could be an illness triggered by an unhealthy diet. Four days later, a local doctor came to see him, leaving a course of antibiotic medicine. In another five days he lost about 25 kilograms in weight. Finally, he was diagnosed with deadly falciparum malaria, the most serious type.

"I had a very hard time. Every time I took one of those pills I suffered a lot of mental stress. So I had to take other pills to keep my mind balanced," he said. "Hearing became sensitive and any noise would make me very uncomfortable."

After the treatment, malaria symptoms disappeared one month later. "However, falciparum malaria is very bad. It can hide in your body. Every time it is awakened, malaria will come again," he said.

Nets and insect repellent can help keep mosquitos away.Photo: CFP

World Malaria Day

April 25 will mark World Malaria Day, which was launched by the WHO in 2007. The purpose of the day is to help countries move towards malaria elimination. The theme for the 2013-2015 campaign is "Invest in the future. Defeat malaria."

According to the figures from a report released by the WHO in December 2013, there were about 207 million malaria cases that caused an estimated 627,000 deaths in 2012. Most of the deaths occur among children in Africa.

"An estimated 3.4 billion people continue to be at risk of malaria, mostly in Africa and Southeast Asia," the report said.

In China, domestic malaria is found in Yunnan and Hainan provinces, the south part of Guizhou Province and the middle area of Henan Province. "Over the past years, China has done well in controlling and eliminating domestic malaria. Beijing is not an endemic area. The last domestic malaria patient the hospital treated was in 2001," Zou said. 

But bigger challenge comes from how to better control malaria cases coming into China from the increasing number of international travelers.

According to figures from the Chinese Center for Disease Control and Prevention, malaria caught outside the country accounted for more than 90 percent of the total malaria cases in China in 2013.

"In 2011, the number of malaria cases from outside the country increased by 92 percent compared with the number in 2010 in Beijing," said Zou. "If diagnosed on time, most malaria patients can be cured in three days. The chance of dying from the disease is very low," she said.

But malaria can be life-threatening if a diagnosis is delayed.

In February, a Web user called "The shadow of bread tree" posted on Sina Weibo that her 31-year-old husband died at a hospital in Hunan Province due to a coma caused by fever. Her husband had suffered malaria three times while working in Africa.

She told Metropolitan in a Weibo message that her husband died from falciparum malaria because he had not received medical treatment on time.

Prophylactics

According to Zou, there is no medicine or other measures that are completely effective in preventing people from catching malaria.      

The mosquitoes also adapt. "In the past, mosquitoes in Africa wouldn't move into areas with the temperatures under 16 C, so people always stayed in air-conditioned rooms. However, people are noticing mosquitoes have started to be active, even in air-conditioned rooms," said Zou.  

This year, the WHO also hopes to raise people's health concerns on the dangers caused by other diseases carried and spread by mosquitoes, flies, ticks, water snails and other insects.

The World Health Day on April 7 this year had the slogan "Small bite, big threat," highlighting the serious and increasing threat of insect-borne disease including malaria, dengue, leishmaniasis, Lyme disease and yellow fever. According to a report released by the WHO in April, "more than 1 billion people are infected and more than 1 million die every year from vector-borne diseases." The diseases are spread by people, insects and microorganisms.

The report says that new groups of people - tourists and business travelers - are vulnerable to the vector-borne diseases.

The Centers for Disease Control and Prevention of the US recommend travelers to consider taking anti-malaria pills in accordance to their destination. It also suggests taking measures to avoid bites.

On the official website of WHO, travelers can download a guide which gives suggestions to malaria prevention measures for different regions.

In 2009, Nimri caught dengue fever when he travelled to Chiang Mai in Thailand. That time, he was doing a 50-day meditation practice at a local temple. It was during raining season of Thailand in August, and he was bitten by mosquitoes.  

"I swiftly went to the hospital. But it still took one month to recover," he said. "The only way to protect yourself from the diseases is to try every method to keep away from mosquitoes."

Avoiding mosquito-borne disease

The Beijing International Travel Healthcare Center gives these tips on avoiding malaria and other vector-borne diseases.

1 Take preventative medicine suitable for the regions you will travel to.

2 Bring mosquito repellent and avoid insect bites. Most of the mosquitoes infected with malaria are active at dusk and night. But the yellow fever mosquito is also active at daytime.

3 Don't wear shorts or sandals. Stay in a closed room with air-conditioning. Use a mosquito net.

4 After returning, people who experience fever, rash, difficulty in breathing, unconsciousness, persistent cough, vomiting, diarrhea, severe unexplained bruising or bleeding should see a doctor immediately.

5 If you feel uncomfortable two weeks after traveling, please tell the doctor where you have been.

(Source: The Beijing Daily)