Beirut, Lebanon - The risk of cholera spreading in Lebanon is "very high", the World Health Organization warned Wednesday, after a case of the acute and potentially deadly diarrheal infection was detected in the conflict-hit country.

The WHO highlighted the risk of cholera spreading among hundreds of thousands of people displaced since Israel escalated an air campaign against Hezbollah and launched a ground offensive intended to push the group back from its northern border with Lebanon.

"If the cholera outbreak … spreads to the new displaced people, it might spread very fast," Abdinasir Abubakar, WHO's representative in Lebanon, told reporters in an online news conference.

Lebanon's health ministry said a cholera case had been confirmed in a Lebanese national who went to the hospital on Monday suffering from watery diarrhea and dehydration.

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The patient, from Ammouniyeh in northern Lebanon, had no history of travel, the ministry said.

Lebanon suffered its first cholera outbreak in 30 years between 2022 and 2023, mainly in the north of the country.

The disease, which causes severe diarrhea, vomiting, and muscle cramps, generally arises from eating or drinking food or water that is contaminated with the bacterium, according to the WHO.

The UN health agency has for months been warning that the disease could resurface amid "deteriorating water and sanitation" among the displaced and their host communities, Abubakar said.

The number of displaced swelled even before the escalation last month, as Hezbollah exchanged cross-border fire with Israel over the past year, saying it was acting over Israel's war on Gaza.

While people in northern Lebanon had recently been exposed or vaccinated, Abubakar cautioned that some communities on the move from southern Lebanon and the Beirut area had not built up any cholera immunity for three decades.

If the disease gets into those populations, he warned, "the risk of spread is very high".

WHO chief Tedros Adhanom Ghebreyesus told reporters the agency had strengthened "surveillance and conduct tracing, including environmental surveillance and water sampling".

In August, he said, the Lebanese health ministry launched an oral cholera vaccination campaign targeting 350,000 people living in high-risk areas, but the campaign was "interrupted by the escalation in violence".