Gu Yanan and Xiao Chu took off their protective clothing, walked out of Ward C, and discussed the next plan of action in the courtyard.

Xiao Chu: "Sister Yanan, what should I do now?" There are too many patients, and we go to the patients' homes one by one to do the flow survey, and the two of us don't have enough manpower. ”

"At present, the patients are mainly distributed in three districts, and according to the principle of local jurisdiction, the CDC in the district will be notified and let them conduct a flow survey of the patients within the jurisdiction."

"What about the two of us?"

"Go to the house where you feel like ten thousand ants are gnawing." Gu Yanan made a look of being bitten by insects and feeling uncomfortable.

Xiao Chu remembered Li Xiaoya's appearance just now, Gu Yanan was talking about that family, "Go to Wang Yunhao and Li Xiaoya's house?" ”

"Yes, Li Xiaoya said just now that before Wang Yunhao became ill, their pigs had died, and this time it may be zoonotic, go to his house to investigate, and there should be a discovery."

According to Gu Yanan's action plan, the two drove to Wangjia Village on the outskirts of Xicheng District.

On the way, Xiao Chu followed Gu Yanan's instructions to call several district disease control and control departments, sent the list of patients, and asked them to go to the patient's home immediately for investigation.

When he was about to arrive at Wangjia Village, Gu Yanan received a call from Wang Xiaoxiao.

On the phone, Wang Xiaoxiao's voice was slightly anxious, "Sister Yanan, many patients with similar symptoms have been reported on the Internet during the epidemic, and they are distributed in all large and small hospitals in the city. ”

Gu Yanan heard that this was the trend of the spread of the epidemic.

The causative source should be identified as soon as possible.

Gu Yanan: "Xiaoxiao, you now send me the list of new cases and detailed information reported in the epidemic network, and at the same time notify each county and district CDC to conduct a flow investigation of the new patients in their jurisdiction, and then notify Zhou Lao, Gao Fei and Lu Li to suspend the on-site supervision of nucleic acid testing capacity, and the focus of the work is on this epidemic, so that they can help the local county CDC to conduct on-site investigation." ”

Ending the call with Wang Xiaoxiao, Gu Yanan and Xiao Chu arrived at Wangjia Village.

At the west end of the village, Wang Yunhao's home.

According to Li Xiaoya's prompt before, Gu Yanan found the door key under the stone slab of the flower bed in front of the door.

Before opening the door, the two changed into protective clothing.

Pushing open the door, there was a frantic barking of dogs.

Xiao Chu took a step back in fright, Gu Yanan looked into the yard and found that there were two big yellow dogs chained in the corner of the yard.

"Don't be afraid, dogs are on a leash." Gu Yanan comforted Xiao Chu.

Xiao Chu bravely walked into the yard and found that the two big yellow dogs were leashed, and their stomachs were very hungry.

When the two big yellow dogs saw the stranger intruding, they first barked a few times, and then they couldn't keep up with their strength and turned into a low moan.

"Good dog, don't bark, we are here to investigate, investigate the cause of your master's illness, and find something to eat from the kitchen to feed you when we leave."

The two big yellow dogs seemed to understand Xiao Chu's words, and lay on the ground and stopped barking.

Xiao Chu looked around and found that the yard of this farmhouse was very large, and there was a door on the west side of the yard, which was half-hidden, and through the crack in the door, rows of pigsty could be seen, and there was a faint sound of pigs.

On the east side of the yard were several large cauldrons with paste-like food residues, apparently prepared for pigs.

Gu Yanan explained to Xiao Chu the precautions for on-site flow investigation, "Pay attention to safety when sampling, this time it may be zoonotic, arthropods may be vectors, if arthropods are found during the sampling process, pay attention to collection." There is also a collection of food that Wang Yunhao's family has eaten and the food that pigs have eaten, to see if there is anything in common, and the possibility of food poisoning cannot be ruled out. ”

"Okay, this time we're going to go our separate ways?"

Xiao Chu has this question, mainly because in the past, when he was on the spot, he was always by Gu Yanan's side, this time Gu Yanan explained the precautions on the scene in advance, which means that the two are responsible for different sampling locations, which saves time.

"Well, I'll go to the pig farm to check the pig deaths, and you are in charge of Wang Yunhao's home sampling, focusing on kitchen food."

Because it was suspected to be a zoonotic disease, Gu Yanan assigned samples from more dangerous pig farms to himself.

"Understood."

Pig farm next door.

Gu Yanan first checked the overall situation of the pig farm in a general circle and found that the dead pigs were all concentrated in the same pigsty.

Were these dead pigs kept in a pigsty before they were born? Or was it dragged to the same pigsty after death?

Gu Yanan inspected the pig carcasses and found that most of the pig carcasses had stiffened and appeared corpse spots, judging from the situation of the corpse spots, the pigs had not been moved, and they had been kept in the same pigsty before they got sick.

Pigs in the same pen are sick and dying, but the pigs in the adjacent pens are healthy.

Could it be a zoonotic disease that spreads in close proximity?

At the very least, the disease should not spread through the air.

So what is the pathogen?

How do pigs in a pigsty become infected at the same time?

How did the pig transmit the disease to Wang Yunhao's family?

If it is really zoonotic, how are other people in the urban area infected?

Is it because of contact with pigs? Or have you ever been exposed to pork products?

Have there been similar cases of sick and dead pigs in other pig farms?

……

A series of questions appeared in Gu Yanan's mind, and these were all questions that needed to be solved.

Gu Yanan opened the sampling box and sampled the dead pig.

The nasopharyngeal swabs and excrement of the dead pigs were fought for with a puncture needle.

Checking the surroundings of the pigsty, many flies and mosquitoes were found.

These arthropods are common vectors of disease.

Gu Yanan took out a sticky fly board and a mosquito trap and hung them on top of the pigsty.

After that, we began to collect soil and water samples from the surrounding area, and finally the trough.

There are more than 20 pens in the farm, which means more than 20 troughs.

Gu Yanan sampled them one by one and found that the food in the pigsty trough where the dead pigs appeared was different from the food in the trough of other pigsties.

The food in the pens trough where the dead pigs appear is black, while the food in the other troughs is dark yellow.

Could it be that the death of pigs has something to do with food?

Originally, the possibility of food poisoning could not be ruled out in this outbreak.

The black food in the trough of the dead pigsty is the focus of laboratory testing.

After collecting samples in the pigsty, Gu Yanan followed the clue of black food and returned to the shed on the east side of Wang Yunhao's small courtyard, which was the place used by Wang Yunhao's family to prepare pig food.

There were also a lot of pig food residues in several large cauldrons under the shed, and the food in one of the pots was blackened, and the food eaten by the dead pigs in the pigsty should have been cooked from here.

There is also a small warehouse on the inside of the shed, and when you open the wooden door, you will find that it is full of sacks of all sizes.

Some sacks are open and are the raw materials for pig food being used.

The sack contained a large amount of corn, black beans, rye and other miscellaneous grains, some of which had been ground into flour and placed separately.

Then check the other sealed sacks in the warehouse, and you can see that most of them are rye.

If the outbreak is food poisoning, then there may be a problem with the raw materials that the dead pigs have eaten.

Gu Yanan sampled these pig food raw materials one by one, packed them into sampling bags and put them into sampling boxes.

When Gu Yanan came out of the pig food material warehouse, he found that Xiao Chu had also come out of the backyard kitchen.

Xiao Chu was carrying a sampling box and two black-flour steamed buns in his hands.