Judging from the flow survey data, the villagers who fell ill processed wheat for nearly half a month, and although Li Erzhu's family also eats their own processed flour all year round, the last processing was two months ago.

What is the specific problem?

I need to go to the site again.

Gu Yanan planned to go to Li Erzhu's flour mill in Lijia Village early in the morning of the second day to have a look.

In the middle of the night of the same day, the results of various poison screenings in the CDC laboratory came out, and various organophosphorus pesticides, strychnine, aconitine, arsenic, lead, mercury, chromium and other poison screenings were done, and the results were all negative.

The specific cause of poisoning has not been detected.

——

Early in the morning of the second day.

Lijia Village, Guanyun Township, Li Erzhu's flour mill.

Gu Yanan drove his own car alone and parked at the door of Li Erzhu's house.

knocked on the door of the courtyard, Li Erzhu came out, and Gu Yanan showed his work card again, "There are still a few questions I want to know." ”

Li Erzhu and his wife had already met Gu Yanan yesterday, and now they are very cooperative, "Okay, you can ask whatever you want, as long as we know, doctor, do you want to have a cup of tea in the first house?" ”

Li Erzhu's wife was very enthusiastic and wanted Gu Yanan to come into the house to drink tea, but Gu Yanan stood in the courtyard and refused, "Just stand here and ask a few questions, have there been any problems with your flour processing machine compared to before?" ”

Li Erzhu quickly replied, "It's been a very busy month recently, and there are a lot of people who come to make appointments with me to process wheat, but in the past two days, because many villagers are sick and panicked, everyone has no heart to process wheat, so these two days have been free." ”

"Have you had any problems with the machine in the last month? Or in the last month, has there been any situation that is different from before? ”

Li Erzhu's wife reminded Li Erzhu, "Half a month ago, when the neighboring village came to process wheat, wasn't the machine broken? You still repaired it for a long time, and it was repaired early in the morning of the second day, when Li Guangfa's family pulled 100 catties of wheat and waited for more than a quarter of an hour. ”

Gu Yanan is very familiar with the name Li Guangfa, and it is one of the poisoning episodes this time.

Li Erzhu suddenly realized, "Oh, I remember, the flour machine broke down once half a month ago, I tinkered with it for a long time, and it was repaired on the morning of the second day." ”

Sure enough, there are clues.

Gu Yanan asked Li Erzhu to take her to inspect the flour milling machine and explain in detail the entire process of repairs at that time.

Next to the flour processing machine, Li Erzhu re-demonstrated the whole process of maintenance at that time, and explained while demonstrating, "At that time, two gears were broken here, I changed the gears, and added some lubricating oil, and the lubricating oil is this, which I just bought from the town a few days ago, and just unpacked it when the machine was repaired half a month ago." ”

Gu Yanan noticed that there was a lot of oil stains on Li Erzhu's hands and between the two gears that had just been repaired, and the oil stains flowed into the flour processing machine along the gears, which would contaminate the flour coming out of it.

"Show me the lube."

Li Erzhu opened the seal and handed half of the lubricating oil to Gu Yanan.

The lubricating oil was very viscous and brownish-yellow, Gu Yanan fanned the mouth of the bottle with his hand, and a foul smell wafted out.

Gu Yanan suddenly thought of a substance.

Tri-o-toluene phosphate.

This is an organophosphorus compound, abbreviated in English, TOCP, is a light yellow liquid, usually used as a chemical raw material, often used as a plasticizer and a flame retardant for hydraulic fluids.

Poisoning caused by TOCP is extremely rare in China, but it has been reported abroad.

Its toxicity mainly damages sensory and motor nerves, pyramidal tracts and spinocerebellar tracts.

After ingesting TOCP, according to the amount of intake, there will be different severity of clinical symptoms, the mild symptoms are only peripheral neuritis, and the severe ones are paralysis.

The symptoms of the villagers' poisoning this time are consistent with the symptoms of TOCP poisoning described in the literature.

"I'm going to take this bottle of lube back."

Gu Yanan also sampled the oil stain in the flour processing machine and the remaining flour inside, and brought it back to the CDC laboratory that morning.

Because of the specific testing object, the test results of the disease control laboratory came out that afternoon.

TOCP was detected in the patient's blood.

Tri-o-toluene phosphate was detected in the lubricating oil used by Li Erzhu, in the oil stain and residual flour in the flour processing machine, and in the flour of the patient's home.

Moreover, the flour of the patient's family was processed in Li Erzhu's flour mill for nearly half a month.

The flour of non-sick households was negative for TOCP.

TOCP was also detected in wheat bran used to feed chickens and pigs at the patient's home.

The cause of the collective poisoning incident in Guanyun Township was found.

The villagers went to Li Erzhu's private flour processing factory to process wheat, and were polluted by the lubricating oil containing TOCP on the machine, and the villagers ate the contaminated flour and became ill one after another, and the symptoms of the patients were related to the amount of consumption.

——

Lianhai Center for Disease Control and Prevention, Emergency Office.

From receiving the report of the poisoning epidemic in Guanyun Township to finding out the cause, the emergency team only took two days, Gu Yanan fed back the test results from the laboratory and the results of the on-site flow investigation to the hospital, and the doctors treated the organophosphate poison, and the patient's symptoms began to ease.

Every time the epidemic is over, Gu Yanan will write a summary report of the epidemic, and this time is no exception.

An investigation into a poisoning incident involving contamination of flour with TOCP lubricant in a private flour mill has been concluded.

After writing the summary report, Gao Fei suddenly ran to Gu Yanan with a bag of flour in a hurry.

"Sister Yanan, this is homemade flour that my girlfriend brought back from her hometown, and I also want to test it to see if it also contains TOCP."

Gu Yanan, "Just give it to my colleagues in the laboratory, let them help make it, don't have to tell me alone." ”

Gao Fei's face was a little frustrated, "I just went there, but my colleagues in the laboratory said that the investigation of the poisoning incident has ended, and their reports are all out, and if you want to do it again, you have to nod, and now the unit is very strict with the test reagent tube, if it was done with the sample before, it will be fine, but this investigation has ended, and it is more troublesome to reopen the reagent and open the instrument." ”

Wang smiled: "Gao Fei, have you offended your colleagues in the laboratory?" ”

"Nope."

Gu Yanan thought for a while and asked, "Did you give the honey buns made by your girlfriend to our colleagues in the laboratory in addition to giving us an emergency office?" ”

"Yes, I brought several boxes with me, one in our emergency office, and a few boxes for the laboratory and several other departments in the field where we had work contacts."

"Well, then tell them that the honey buns were made with these same flours, and they'll check it for you. However, there are very few cases of TOCP poisoning, and the private flour processing factory of Li Erzhu's family in Guanyun Township will only occur because of the use of substandard lubricating oil, and the probability of similar examples appearing again is very rare, but in order to reassure everyone's heart, colleagues in the laboratory will definitely do it, you can send it over. ”