A puzzling respiratory virus that has plagued Saudi Arabia caused a surge of deaths over the weekend, triggering fears of human contagion and widespread transmission.

Saudi officials confirmed that 10 people died on Saturday and Sunday from the infection known as Middle East Respiratory Syndrome (MERS), increasing the death toll within the country to 102.

Saudi Arabia has reported some 345 cases since the virus was first detected in 2012. Over the last month, 39 people have died in what appears to be a seasonal outbreak, accounting for more than a third of the total deaths.

Little is known about how MERS is transmitted, and there is no vaccine or specific treatment. Scientists believe the virus originated in camels, and don't think that it is easily spread between humans. Symptoms include fever, coughing, and shortness of breath; the infection can result in pneumonia, diarrhea, and kidney failure.

MERS is similar to Severe Acute Respiratory Syndrome (SARS), which infected at least 8,000 people and killed 775 during a global outbreak between 2002 and 2003. Both illnesses are members of the coronavirus family, which is associated with common colds.

Egypt’s Ministry of Health reported the country’s first case of the virus on Saturday, involving a 27-year-old man who had been living in the Saudi capital of Riyadh. Egypt joined a number of nations where MERS has appeared, including countries across the Middle East and Europe as well as Tunisia, Malaysia, and the Philippines.

Saudi Arabia’s outbreak and the spread of infection across borders have prompted worry about a worldwide epidemic. The World Health Organization (WHO) raised alarm when it reported last week that approximately 75 percent of recent MERS cases were believed to have been transmitted through human-to-human contact.

But Dr. W. Ian Lipkin, the director of Columbia University’s Center for Infection and Immunity, told VICE News that the spring outbreak is not yet a cause for major concern. He noted that human-to-human transmissions have so far mostly occurred in places like hospitals, infecting people who are already ill and vulnerable.

“The fact is we’ve been very fortunate because this hasn’t become more pathogenic,” Lipkin said. “There’s no evidence that this virus is becoming more virulent.”

Lipkin and a team of researchers from Columbia and King Saud University published a study on Tuesday that found definitive evidence that camels are the major source of MERS transmission. While the camel link had long been suspected, the study determined that most camels carry a strain of the virus that matches the one infecting humans. In uncovering this “smoking gun,” the team also found clues behind the spring outbreak.

The recent increase in MERS cases, Lipkin said, is due to testing people more frequently combined with the fact that a lot of young camels are born during this time of year. He explained that camels under the age of two are more likely to contract the virus and transmit it to humans. The study underscored the importance in Saudi Arabia of minimizing contact with camels.

“Given these new data, we are now investigating potential routes for human infection through exposure to camel milk or meat products,” Dr. Abdulaziz N. Alagaili, Lipkin’s co-author and the director of the Mammals Research Chair at King Saud University, said in a statement.

The study has already resonated with the Saudi government, which has been criticized for a lack of action and transparency. It removed its health minister from office last week and pledged to improve its response to the crisis. Adel bin Mohammed Faqih, the new acting health minister, announced in a press conference on Tuesday that the ministry would implement a plan to limit the spread of the virus. He suggested avoiding contact with camels and camel products.

“There has been a consensus during discussions [with experts] over the past two days,” Faqih said, “and there was advice not to get in close contact with camels, especially sick camels.” He advised Saudis to take care when handling raw camel meat, and to not drink camel milk before boiling it.

Another scientific development emerged this week that could help combat the spread of the virus. Researchers at the University of Hong Kong, Tsinghua University, and Sichuan University identified two human antibodies capable of blocking a key MERS protein from entering and infecting cells. The results published in Science Translational Medicine on Monday could help develop a vaccine or treatment.

Experts have nevertheless questioned the practicality of spending millions to create a vaccine for a disease that affects a sliver of the population.

“Who would you vaccinate?” Ian Jones, a virologist at University of Reading, asked Reuters ahead the antibody discovery. “Would you vaccinate the whole population when only a tiny number of people seem to be susceptible?”

Meanwhile, a recent MERS risk assessment by WHO observed that “the occurrence of new cases seems to follow a seasonal pattern,” with increased transmission beginning in March and April.

Dr. Ben Neuman, a virologist at the University of Reading who studies coronaviruses like MERS and SARS, told VICE News that many viruses see seasonal outbreaks, like the flu in winter.

According to Neuman, the mortality rate in the latest wave of MERS infections has dropped from 60 percent to between 30 and 40 percent. A similar drop was registered during the SARS outbreak. The first wave of SARS transmissions was much more deadly than the second and third waves, he explained, even though more people were contracting the virus.

Neuman said that he’s waiting to see how the current outbreak will unfold. The many unknowns of MERS and the potential for viruses to mutate makes monitoring the illness particularly important. The virus can live in someone's system for weeks and be potentially contagious without showing any symptoms.

“Think of how many people you have bumped into or bought coffee from in the last month,” Neuman said.

Follow Kayla Ruble on Twitter: @RubleKB