Interview with microbiologist Raul Rivas

Noemi G. Gomez |

Madrid (EFE).- The detection of the H5N1 avian influenza virus in cattle, the confirmation that it can be transmitted between mammals through contaminated milk, and new cases in humans should be a cause for concern, says microbiologist Raúl Rivas, for whom this “escalation of virus events” means that vigilance must be extreme.

“H5N1 is already a pandemic virus in birds, let’s hope it doesn’t become one in humans,” emphasizes Rivas, a doctor of biological sciences and professor of microbiology at the University of Salamanca, who recently published the book “Microbes and Cancer” with EFE (Guadalmazan).

The researcher explains that there are now many outbreaks in wild birds, more than ever before in history, and in poultry. From birds, the virus has jumped to mammals, small and large, such as sea lions (due to predators attacking dead birds), and a few months ago it appeared on dairy farms in the US, which is “another very worrying fact.”

The discovery of the virus subtype on a dairy farm in the country in the spring represented the first documented outbreak of highly pathogenic avian influenza in cattle. Since then, its spread between herds, to other mammals (cats, raccoons) and even a few new cases in humans have been documented and published in various scientific studies.

“At the moment, with mild symptoms,” says Rivas, who specifies that from 2003 to April 1, 2024, a total of 889 cases of the disease have been registered worldwide, according to the World Health Organization. “This indicates that at the moment, the transmission of the virus from animal to human is not very good, and, in addition, there are no known cases of transmission from human to human,” he says.

But the mortality rate (463 people) is about 52%, “which is outrageous.”

The virus appears to have “difficulty adapting” to humans, but if it infects pigs it would be a “major problem” not only because of the large farms but also because they “act like shakers”.

The cells of these animals have receptors for both bird and human flu. “If these two viruses enter the same cell, recombination can occur between them and another one can appear that can infect humans,” Rivas explains.

This is something similar, the scientist adds, to what happened in 2009 with the “famous influenza A (H1N1) with pandemic potential (…). Fortunately, today it is under control and circulates among the seasonal flu.”

“We are now in a situation of uncertainty and concern regarding H5N1. Therefore, surveillance must continue, appropriate control measures must be put in place, cases of human disease must be detected, and of course outbreaks in animals must be detected.”

The scientist reminds us that vaccines for animals and humans already exist against this flu virus. In fact, he points out, the US is starting to produce them at an accelerated pace and is considering vaccinating workers from risk groups.

However, “the problem is not that a vaccine exists, but, as we have seen with Covid-19, producing it and distributing it on a large scale; it is not easy and it takes time,” says Rivas.

Cancer and Dictatorship

“Cancer is not one disease, but many, caused by the uncontrolled growth of a single cell. In doing so, he recalls dictatorships, past and present, dictatorships of the “I shit in the sea” type, or those who swear to be blessed bread, while putting forward many excuses.”

This is how Rivas begins his latest book, which draws on historical data, scientific literature and, occasionally, entertaining anecdotes to detail the connection between microbes and cancer: nearly 20% of malignant tumors are linked to infection by bacteria, parasites and viruses.

As for cancer, which in the 18th century was associated with emotional excess, “we learn more every day,” he told EFE, but the disease is still “far from being eradicated.” “Another thing is that we can understand some types of tumors by making them chronic and increasing the arsenal of means to combat them.”

For example, pancreatic cancer, which used to be a “death sentence, is no longer one.” Rivas believes that things have changed dramatically in the last few years and will continue to change.

Partly because of data analysis and artificial intelligence. There are already studies that demonstrate the usefulness of AI, for example, in analyzing mammograms and improving breast cancer diagnosis, or in identifying a new class of antibiotic candidates against resistant bacteria.

But AI hasn’t yet become widespread in science, Rivas says. Using the analogy that we are now “like those first Nokia or Motorola cell phones,” he says, “it was incredible, but we need to get to today’s smartphones.” That’s when “AI will become a great tool for science.”

A universal cancer vaccine?

Although research has made great progress, it is not yet possible to create a universal vaccine against cancer; there is no technology for this, and cancer is a variety of different diseases.

What does exist are early clinical trials of experimental vaccines – messenger RNA – for, for example, one form of pancreatic cancer, and of course preventive vaccines against microorganisms that are already on the market. This is the case with the human papillomavirus, which prevents cervical cancer.