Everyone else was very happy, the patient was cured, and the blood prevention work in the epidemic area was also implemented step by step, and Zhang Xiaobin could finally take his parents and little sister home with confidence.

Nan Zhiqiao once again played the role of a driver, driving an off-road vehicle to send Zhang Xiaobin's parents home.

The second time I came to this small village deep in the mountains, my mood was completely different from the last time.

Qianqian shouted all the way to play at Xiaoxian's house for a few more days, and Xiaoxian was also kind to stay.

Xiaobin's parents are very grateful to Nan Zhiqiao and his party for their help during this time, and they warmly retained them, hoping that everyone can stay here for a few more days to fulfill the friendship of the landlord.

Cousin Qianqian was very happy, thinking to herself, after coming to Dali for so many days, she finally has time to play, and she is accompanied by her good friend Xiaoxian, cousin and future brother-in-law.

Ye Zhenzhen's face was very hesitant, not because she didn't want to play here, but mainly because she was worried that she had been away from the laboratory for so many days, and the students didn't know what was going on, whether the daily work of the laboratory was in order, and the most important thing was Nan Zhiqiao, Senior Nan was definitely more worried about the situation of the students in the laboratory, as well as the progress of the Guojing Microbial Forensic Science Laboratory under construction.

To Ye Zhenzhen's surprise, Nan Zhiqiao nodded in agreement.

Xiaobin and Xiaobin's parents were very happy, and began to clean up the room and prepare for Nan Zhiqiao and his party to stay at home.

Although Xiaobin's hometown is located in a remote mountainous countryside with simple living facilities, fortunately, the place is very spacious and there are many rooms at home, so two bedrooms are vacated after a little tidying, one for Nanzhiqiao, one for Ye Zhenzhen and her cousin Qianqian.

After settling down the luggage, Xiaobin's parents pulled Nan Zhiqiao and said something, first thanking him for the help this time, as well as taking care of Xiaobin as Xiaobin's mentor, and then talking about the local customs, two days later is the local annual torch festival, when all the people will gather together to carry out various folk activities, pick up the fire, play with fire, worship the god of fire, bullfighting and wrestling, and there is a large-scale bonfire party at night.

Qianqian was looking forward to the Torch Festival, and Nan Zhiqiao promised to return to Beijing after the Torch Festival.

Ye Zhenzhen felt that Senior Nan was delaying the time to go back because of Qianqian, and she was very sorry, but Nan Zhiqiao said that she decided to stay for a few more days because she had something to do, and it had nothing to do with Qianqian.

It must not be a simple matter for Nan Zhiqiao to decide to stay here for a few more days, Ye Zhenzhen is very curious.

Nan Zhiqiao told Zhen Zhen what was on his mind, it turned out that although the schistosomiasis epidemic had been controlled, the most important link in the spread of the epidemic, the intermediate host snail, suddenly multiplied in large numbers, and carried schistosomiasis cercariae, turning a large area of water into infected water, and almost polluted the Erhai Lake.

Ye Zhenzhen felt that the snail grows naturally under natural conditions, and it must be because the external environment is suitable to cause the large-scale reproduction of the snail.

First of all, this large-scale schistosomiasis outbreak is concentrated in time and place, and the distribution of snails as an intermediate host is also relatively concentrated, which shows that there must be some inducing reasons in the affected water area, secondly, the symptoms of acute schistosomiasis patients are different from the past, there are widespread ectopic parasitism and ectopic damage, and finally, most importantly, the newly discovered schistosomiasis DNA has obvious mutations, whether it is natural mutation or artificial mutation, it is necessary to investigate the source of snails。

Ye Zhenzhen was persuaded by Nan Zhiqiao's reason, but where to start?

Nan Zhiqiao had already made up his mind about the source of the canal he had been to last time, which was where the Mid-Levels Waterfall was located.

This time I went to the waterfall to investigate the source of the snail, and there were only three people, Nan Zhiqiao, Ye Zhenzhen and Zhang Xiaobin.

Qianqian was taken around the village by Xiaoxian, Xiaobin's father had already gone to work in the field, and Xiaobin's mother went to the vegetable garden to buy vegetables and fruits, ready to entertain guests at night.

The second time I went, because I was familiar with the road, I walked very fast, and it took more than half an hour to reach the bottom of the cliff in the middle of the mountain where the waterfall is located.

The roar of the waterfall drowned out all the sounds around her, and Nan no Qiao circled half a circle around the waterhole under the waterfall.

The water of the pool on the shore is clear and transparent, but through the pool water, you can clearly see the shallows at the bottom of the water, and the small snails at the bottom of the water are still dense, and many of them are moving with pseudopods.

The three of them all saw the snails on the shore, and Ye Zhenzhen asked loudly: "Isn't there already a snail extermination operation here, why are there so many snails?"

Zhang Xiaobin also echoed: "I heard from the people in the village that people from the disease control department have come to the village to publicize the knowledge of blood prevention and snail extermination, people and animals have taken chemotherapy drugs, and the canals here have also sprinkled snail killing drugs, like niclosamide, also called blood prevention -67, it stands to reason that the density of snails here has dropped by at least 80 percent, but depending on the current situation, there are more snails than when I came last time." ”

Nan Zhiqiao frowned slightly, "These snails are very small, they should have just been bred." ”

Ye Zhenzhen and Zhang Xiaobin were both shocked, this snail kept appearing, so the source of its reproduction must be in a place that was not involved in drug spraying.

Thinking of this, the three of them looked at the upper reaches of the waterfall at the same time.

The last time I came, everyone had been to the upper reaches of the waterfall, and no snails were found there, so the information was fed back to the local disease control, and the people from the disease control did not go to the upper reaches of the waterfall to spray snail killing drugs.

The three of them walked along the stone path not far from the waterfall to the meadow upstream of the waterfall, and Grandpa Zhang's cabin appeared in front of him again, and in the grass next to the wooden house, various streams with different directions finally converged on the edge of the cliff to form a waterfall.

It is said that it is a meadow, but it is more like a swamp, where water flows under the meadow, and where the water flow is large, it forms a stream, and where the water flow is small, it looks like a calm swamp.

The water in the meadows is usually accumulated in rain or seepage from the surrounding mountains, and although the water flow is slow, the total water capacity is large.

In order to find a place for the snails to breed, the three people acted separately, each in charge of an area, and for the sake of safety, the three people were not far away, a certain distance, and they could go hand in hand, and they could take care of each other.

Stepping into the wet grass, there is no slimy feeling that you can't pull your legs, but there are hard stones under your feet, only a thin layer of soil on top, in which the roots of various weeds and wildflowers grow.

Although the soil is thin, the water contains nutrients that are abundant in the high mountains, so the grassland depends on the nutrients seeping out of the surrounding mountains, and grows year after year.