Chinese health workers are fighting a major battle against outbreaks of meningitis, hepatitis and other infectious diseases apparently aggravated by recent political turmoil.

Alongside busy streets and across from the Canton No. 1 People's Hospital, large posters in this South China city of 2 million warn of a meningitis "epidemic situation." Doctors here and in the suburbs of Shanghai, 850 miles to the north, report unusual numbers of hepatitis cases. Peking sources have reported as many as 30,000 cases in Canton late last year.

The two debilitating diseases, which the Chinese are fighting with a vigorous public information campaign, have apparently spread during the disruption of last year's struggle by Mao's widow Chiang Ching to succeed her husband as leader of the country.

After considerable success in the past combating filth and insects, the Chinese appear to have slipped back into bad habits. Health authorities in much of the country appear to have been distracted by the political battles and by the removal later last year of the minister of public health, apparently an ally of Chiang Ching.

Foreign veterans of the Chinese export commodities fair held here twice a year say disease carrying insects, particularly mosquitos, have multiplied considerably this season. Small clouds of mosquitos swarmed around guests at a fashionable lakeside open-air restaurant one recent evening. Canton authorities have posted health regulations in several parts of the ciyt that emphasize "getting rid of mosquitos . . . and gaining tight control over their breeding grounds."

Spring clean-up campaigns have been used in the past to tighten up health standards in China. But the public health program is receiving extraordinary emphasis this year because of previous confusion and neglect balmed on Chiang and the rest of the "Gang of Four," Chinese doctors here and in Shanghai say.

Asked about the hepatitals problem, Dr. Huang Huo-wen of the Chungshan Special Tumors Hospital here said "due to the Gang of Four's interference, patriotic mass sanitation work failed to be carried out well. So recently we found a lot of flies and mosquitoes, and it is up to us to control them." The hepatits outbreak, he said, "is hard to control. We see many cases."

A circular issued by the State Council in Peking April 5 said that as a result of the "Gang's" interference, "public health work met with great setbacks in the past few years and the patriotic health campaign was neglected."

Teen-age girls waving small banners and shouting into bullhorns walked up the main waterfront boulevard of Shanghai one day late last month demanding renewed efforts at cleaning, out insects and vermin. Reports from Peking earlier this month said that a poster campaign has begun to combat a threatened epidemic in earthquake shelters there. The official Chinese new agency reports serious neglect last year of efforts to eradicate a serious snail-borne disease.

Canton's public health regulations, posted in the form of "Six Dos" and "Six Don'ts," show that there is room for improvement. "Don't rear dogs in the city," the regulation advises, although dogs are often seen in city streets.

"Maintain the peacefulness of the city and try to reduce noise volume to a minimum," it advises, while taxicabs and trucks continue to follow the Cantonese practice of blowing their horns every half-block.

"We must struggle and fight against anti-public health and against anti-public order behavior," the health regulations poster, dated April 29, said.

One poster on meningitis said: "In nursery and childcare centers, checkups must be made in the morning. Upon discovery of suspected child patients, the crild must be separated immediately and the closely observed. In the new industrial, agricultural and irrigation sites, and in big residential units, health service must be strengthened. Close observation must be made concerning the epidemic situation and all preventive measures must be enhanced."

An April 12 broadcast from Canton said delegates to a local health conference "demanded that the management of drinking water, rubbish, night soil and sanitation in the catering trade be strenthened."

In an interview, Dr. Chen Lung said his hospital in Chiating County, a suburb of Shanghai, had also gotten an unusual number of hepatits patients because of unsanitary conditions he blamed on sabotage of public health coordination by political opportunists. In late April his hospital had 25 cases.

The doctors' frank discussions of their health problems seemed to reflect a new candor among officials interviewed during a two-week tour of China. A nurse who has treated foreign students in Peking in the past, and found an unusual incidence of hepatitis, said the Chinese last year were very reluctant to admit they had such a problem.

Several American doctors who have visited China, including Arlington Va., physician Tom Connally, said they have noticed that paramedics in the countryside - called "barefoot doctors' by the Chinese - are using alcohol to clean the needles they stick into patients skin for acupuncture treatments. The doctors argue the Chinese are risking a form of hepatitis contracted from improperly sterilized needles and suffered by many American drug addicts.

"You can't just wipe the needle with alcohol to remove the danger of hepatitis," Connally said in an interview. "You must take them back to a hospital to adequately clean them" in a steam heating device.

Chinese doctors here an in Shanghai said they used such devices to sterilize needles in their hospitals, but acknowledged that health workers in the country used alcohol.

"We think that is sufficient," said Huang. "What we are worried about is unsanitary conditions in the preparation of food."

Hepatitis is thought to be commonly caused by a virus that attacks the liver, producing fever, nausea, marked fatigue and sometimes jaundice. Connally said several Chinese he met in 1974 seemed to show hepatitis symptoms.

He also got the impression that China was experiencing a high liver cancer rate, which could be linked to hepatits, but Chinese doctors interviewed last month said liver cancer was not an unusual problem. Other American health experts who have visited China recently said they did not ask about hepatitis.

Meningitis is an infection of the membrance that covers the brain and spinal cord. Its first symptoms are often fever and headache, but if untreated it can lead to serious brain damage or death. One Canton wall poster recommended a modern drug, sulfadiazine, and several traditional Chinese herbal medicines to prevent the disease.

Recent visitors to Canton found the city carrying on its public health campaign at a time of serious drought. Reservoirs were low, city authorities said, partly because of the drought and partly because they had been partially drained during an earthquake alert last year.

This reduced the electricity generated by reservoir dams. And some parts of the city were without power during part of the week. "You notice our streetlights aren't lit. Because of the water shortage we have to save power for the countryside. But we will get over that," one official said.

As for food supplies, stocks at markets and the dinner tables of families visited at random indicated that people in the Canton, Shanghai and Peking area had enough rice.

"I got 33 pounds last month and I didn't use it all," said one Canton official. "There are some limits on meat, but when the supplies are greater, we can eat as much as we like."

Few if any foreign visitors have been allowed to check conditions in provinces like Szechwan or Fukien, said to be hardest hit by breakdowns in farm production brought on by last year's political troubles. Leaders of the Fangtai production brigade outside Shanghai, who complained in interviews of severe interference by the "Gang of Four," still claimed to have enough grain in reserve to feed the 2,000 brigade members for seven months.

At Ahansi Province's Tachai production brigade, now the model for all farming villages in China, grain stocks were full and rain had just fallen on newly sown corn seed when visitors dropped by in late April. Did they have enough meat? "Well, that's hard to say," said a brigade official. "So many of us are vegetarians."