To find out the cause, it is necessary to conduct a flow investigation of the recent insect-borne disease, and with so many patients, it is necessary to ask the medical history and the contact history during the onset period one by one.

The staff of the district CDC were responsible for the investigation of the patients in various suburban hospitals, and several patients from JS Hospital were handed over to Ye Zhenzhen.

Inside JS Hospital, Ye Zhenzhen is asking the inpatients involved in the insect-borne disease outbreak one by one.

And Nan Zhiqiao made a warning notice based on the recently discovered epidemic, " In view of the recent outbreak of dengue fever and other insect-borne diseases in the western suburbs, and the recent mosquito vector monitoring results in China also show that the Breto index exceeds 10 in many places, 20 in some areas, and 30 in some areas, all localities are requested to strengthen the monitoring of dengue fever and other insect-borne diseases, do a good job in the training of relics personnel in clinical institutions within their jurisdiction, once imported cases occur, they should do a good job of emergency testing in a timely manner, and report local infection cases by telephone in a timely manner; and in accordance with the requirements of the national guidelines for the prevention and control of dengue fever and other insect-borne diseases, the areas with a Bretu index of more than 10 should take mosquito control measures to prevent the emergence of major epidemics。 ”

Here, Nan Zhiqiao issued warning notices to various places through the disease control network, and Ye Zhenzhen's disease investigation also had some eyebrows.

After questioning the patients, all of them had one thing in common, that is, they had been to the vicinity of the Western Suburbs Zoo before the onset of the disease.

Ye Zhenzhen remembered that Duoduo from the children's welfare home before was paralyzed by a tick bite after going to the Western Suburbs Zoo and having a picnic nearby.

Grandpa Nan and Grandpa Sun, who had also been to the valley woods near the Western Suburbs Zoo, were also bitten by ticks and mosquitoes, and although the ticks were found in time, they were still infected with insect-borne diseases.

Other patients have had similar experiences.

Intuition told Ye that there must be clues related to this insect-borne disease outbreak near the western suburb zoo.

Nan Zhiqiao analyzed from a professional point of view, and it is imperative for the Western Suburbs Zoo to go.

——

The next morning, Nan Zhiqiao and Ye Zhenzhen took the box of the flow and drove the off-road vehicle to the Western Suburbs Zoo.

The Western Suburbs Zoo is a wildlife park, located in the western suburbs of 10,000 acres of forest, is a collection of animal protection, wild animal domestication and breeding and popular science education as one of the large-scale natural ecological park.

For the investigation of the outflow of the western suburbs zoo, Nan Zhiqiao first greeted the park, and the park was very cooperative and helped the flow as much as possible.

The key to the investigation of insect-borne diseases is the investigation of vector insects.

Humans are not the source of infection of insect-borne infectious diseases, and vector insects are the basic way for humans to be infected with insect-borne infectious diseases, so after the two entered the zoo, they first had to sample the vector insects.

Originally, the district CDC was responsible for sampling vector insects in the epidemic area, but Nan Zhiqiao was worried that someone had missed important clues, so he came in person.

Nan Zhiqiao personally came to the Western Suburbs Zoo for another reason, which was the fear of the simultaneous outbreak of several insect-borne diseases.

The two placed an unequal number of mosquito traps on the forest slopes of the western suburbs zoo, and examined the animals in the zoo for ticks and other parasites.

From morning to noon, Nan Zhiqiao and Ye Zhenzhen were still busy in a forest in the western suburbs of the zoo.

When the sun was in the sky, Nan Zhiqiao fixed the last mosquito trap in his hand, turned back and shouted to Ye Zhenzhen who was not far away: "Zhenzhen, go to the car and take a rest." ”

After a busy morning, Ye Zhenzhen was also tired and hungry, and when she heard Nan Zhiqiao's greeting, she hurriedly finished sorting out the work in her hand and ran to the car that came from her.

When the two of them came in the morning, they planned to spend the day outside, so they brought lunch with them in the car.

Lunch was simple, just sandwiches, fruit and mineral water.

After having lunch in the off-road vehicle, Nan Zhiqiao remembered Grandpa Sun's words, "That dead wild dog seems to have escaped from a nearby zoo." ”

If, as Grandpa Sun had speculated, the wild dogs were able to move freely between the zoo and the nearby valleys, then there may be clues to the outbreak of insect-borne diseases in the nearby valleys.

When the work at the Western Suburbs Safari Park comes to an end, Minami no Joe proposes to visit the valley near the zoo.

Ye Zhenzhen immediately understood what Nan Zhiqiao meant, "Senior Nan, is it the place where Grandpa Sun digs orchid grass and buries wild dogs?"

"Yes, there it is. ”

Ye Zhenzhen also had this intention, and the two hit it off, driving an off-road vehicle from the fork in the western suburbs of the safari park to the nearby valley.

The Western Suburbs Safari Park is a few hills circled in a forest, leaving the zoo, there are really many valleys around, the mountain roads in the forest are rugged, and the off-road vehicles are bumpy all the way.

Nan Zhiqiao turned on the GPS positioning system on the car, and compared with Grandpa Sun's description of the valley, the off-road vehicle bumped in the forest for more than an hour before finding the valley.

A V-shaped valley is sandwiched between two hills, and at the entrance to the valley is a large fan-shaped slope covered with low shrubs and wild orchids.

Standing at the entrance of the valley, Ye Zhenzhen looked at a large field of orchids in front of her, the tender green leaves were dotted with white flowers, and there was a sense of quiet beauty of the hollow valley orchid.

Ye Zhenzhen sighed: "So many orchids and grass! Grandpa Sun dug it here." ”

Nan Zhiqiao: "It should be in the valley, there are ordinary orchids and grasses here, and the one that Grandpa Sun brought back is very rare." ”

"Then let's go into the valley and catch a few mosquitoes. ”

Ye Zhenzhen took two mosquito traps, walked through the orchid grass slope, and burrowed into the valley.

Nan Zhiqiao took down a tool axe from the off-road vehicle to open the road, and after entering the valley, the trees were thick, and the axe came in handy.

The dead branches accumulated over the years were piled up on the ground, and the branches were cut off with axes to open the way.

Passing by a fork in the road formed by a mountain stream, Minami Zhiqiao stopped, observed slightly, and chose to continue walking in a southwestern direction.

A short distance into the valley, the two of them walked for more than half an hour.

Nan Zhiqiao opened the road in front, Ye Zhenzhen followed behind, and sighed: "Senior Nan, the road in this valley is so difficult to walk, how did Grandpa Sun and Grandpa Nan get in?"

Nan Zhiqiao cut another branch in front of him, freed up a small path, and after a moment of respite, he replied, "We just went in the other direction at the bend in the valley. ”

"Ahh

Nan Zhiqiao shook his head, "No, I deliberately went this way." ”

"Why?"

"I think it's better for catching mosquitoes. ”

Nan Zhiqiao stood still and commanded, "Hang the mosquito trap near here." ”

Walking all the way just now, Ye Zhenzhen had long felt that the mosquitoes here were big, numerous and ferocious, and many mosquitoes were circling around.