Always prepared for the unexpected

12 Nov 2021

Camilla Rothe was one of the first to recognize and report asymptomatic transmission of Covid-19. Dealing with unknown infectious diseases is part of the job for a specialist in tropical medicine.

The photo shows Dr. Camilla Rothe

Dr. Camilla Rothe | © LMU

“We must be constantly on our guard,” says Dr. Camilla Rothe, who heads the Outpatient Department in the Hospital for Tropical and Travel Medicine at the LMU Medical Center. She made a discovery in relation to the SARS-CoV-2 virus early last year, which would change the world (and in this case, the hackneyed phrase is justified). – But then, Covid-19 is not the only “imported” infectious disease that Rothe has encountered in her career. “Only a few years ago, the world was taken by surprise by the Zika virus, which is transmitted by mosquitos. Like the related dengue virus, Zika causes fever and joint pain – but it can also induce severe congenital malformations in human embryos.” In addition to the emergence of novel infectious agents, Rothe and her colleagues have observed that known pathologies now turn up in unexpected locations, as a result of human migrations. She therefore argues that general practitioners should have easier access to the expert knowledge accumulated by specialists in tropical medicine.

Rothe regards herself “primarily as a clinician, university teacher – and ‘occasional’ researcher”. Nevertheless, her many contributions to research deal with topics as diverse as the treatment of a specific form of meningitis in Malawi, infections that are frequently transmitted within the healthcare systems in Sub-Saharan Africa, and worm infections such as lymphatic filariasis in the tropics. “My publications list is so heterogeneous because I have studied the intriguing cases that I came across in the course of my daily rounds as a physician.”

The case that appeared on January 27, 2020 was a very special one. The patient, a 33-year-old male, had developed a mild cold over the weekend, and came into the Outpatient Department on the Monday. By then, he had essentially recovered. But he wanted to make sure that he hadn’t picked up the novel respiratory disease that was then circulating in Wuhan. – He explained that he worked for an automotive supplier, and that a Chinese colleague who had visited the company during the previous week had tested positively for the new virus on her return home.

“In the Institute of Tropical Medicine, we are always conscious of, and prepared for, the possibility that a novel infection can turn up at any time,” Rothe explains. “We study reports on outbreaks from around the world, and we try to assess their propagation potential, and how best to protect the local population in the event that they get this far.” The Institute in Munich was already alert to the possibility that Covid-19 could reach Germany. Descriptions of the symptoms in several languages were prominently displayed at the entrance to the building, accompanied by the (now familiar) request that persons with such symptoms should avoid the waiting room. When Camilla Rothe took a swab from the employee of the parts firm in an isolation ward, she was equipped for all eventualities, swathed in protective clothing, including FFP2 mask, hood and gloves. The sample was sent to the Microbiology Department in the University of the German Armed Forces in Munich for PCR analysis. “That was before you could be tested for Covid on virtually every street corner,” Rothe points out.

An inference with alarming implications

Although Rothe was prepared for the worst, she was surprised when she received the news that the test had come up positive – and she interviewed the patient at length. It emerged that his colleague from Shanghai had shown no symptoms of illness in the course of several hours during which they had worked together. Representatives of State agencies who had spoken to the Chinese visitor on the telephone confirmed this – and Rothe came to the conclusion that the novel disease could be transmitted by individuals who showed no overt symptoms of the condition.

“The implications of the positive result were alarming,” says Rothe, for up to that point it had been assumed that only symptomatic individuals could transmit the new coronavirus to others – as was true of the related SARS virus that emerged in 2003. “It meant that people who were infected but displayed no symptoms were criss-crossing the globe and inadvertently infecting others. So my – essentially quite elementary – inference was actually an explosive one.” She promptly informed the health authorities, and her observations were published in the New England Journal of Medicine within a few days. “It was immediately clear to me that the finding had to be communicated to the rest of world as fast as possible.”

In the days following the appearance of the paper, the telephones in the Institute never stopped ringing. Not only had Rothe diagnosed the first case of Covid-19 in Germany, she was also the first physician in the Western world to clearly describe a case of transmission of the disease by an asymptomatic patient. This explains why so many of the callers were representatives of the media. “As if we didn’t have more than enough to do, in addition to the usual clinical routine! For example, we brought students along with us to two nursing homes, took swabs from the staff and explained the precautions to be taken to prevent the spread of the infection.”

While her family and her colleagues responded positively to Rothe’s recognition that Covid-19 could be transmitted by asymptomatic carriers of the virus, others were far from convinced. “The findings prompted various forms of abuse in some of the media,” she recalls. Even government agencies in the UK and Sweden cast doubt on the validity of Rothe’s inference. “That was a rather extreme reaction,” she says, “but many people just didn’t want to hear or accept that patients who showed no symptoms of infection could transmit this virus.”

Six months later, by which time Rothe’s conclusion had been confirmed worldwide, the pendulum changed direction. The New York Times (NYT) published a front-page article entitled “How the World Missed Covid-19's Silent Spread”. The report, together with other reports on the pandemic that had appeared in the paper, went on to win the Pulitzer Prize for Public Service. Based on her seminal discovery, TIME Magazine subsequently included Rothe on its list of the 100 most influential people in the world in the year 2020. – And at home, she received the award Pro meritis scientiae et litterarum” from the State of Bavaria. She herself found that all the fuss was a bit too much. “I hadn’t sequenced an important gene or cloned a new mouse strain. I had just taken another look and put two and two together. – Nothing special, all in a day’s work.”

Winds of change

Rothe’s choice of career was markedly influenced by her experiences in Kenya. A native of Heidelberg, she developed an early interest in other cultures and in the social problems with which the world’s poor are confronted. As a medical student, she worked for a time in a hospital in Nairobi. “That was in the late 1990s, when large numbers of people were dying of AIDS.” The hospital in which she sat in on lectures for two-and-a-half months was a public institution, funded by the State. But to her it seemed more like ‘a huge hospice’. “Wards were overcrowded, with several patients sharing each bed, and the doctors could do little for them. It was almost apocalyptic, and it made a deep impression on me.”

Her unforgettable encounter with HIV patients in Kenya led her to work on the virus in her doctoral research project at the Free University of Berlin – while at the same time undertaking her specialist training in internal medicine with a focus in infectious diseases in the Institute of Tropical Medicine at the Charité. She then spent four years at Queen Elizabeth Central Hospital in Malawi (one year would have sufficed for her accreditation as a specialist in tropical medicine). On her return to Germany, Dr. Rothe found a position in the Outpatient Department at the Bernhard Nocht Institute of Tropical Medicine in Hamburg. She moved to the LMU Medical Center as an Assistant Medical Director in 2017.

Much has changed in the department since that first Covid-19 patient consulted her in January 2020. “Normally, she says, we are one of the busiest walk-in centers for travel medicine in the country,” she says. But since the numbers of people returning from abroad have fallen drastically since the arrival of SARS-CoV-2, a new unit devoted to vaccine research has now been established. “In future, we will also work on the development of vaccines specifically for tropical diseases – so the disruption of our routine has also had a positive impact.”

“I’m pleased to say that none of my family or my colleagues (my second family) has been infected with the virus,” she says. “In the outpatient section of a department like ours, that’s quite amazing, considering that we have been on the frontline of the battle against the virus from the very beginning.” – But she knows that another pathogen with the potential to spread across the globe may emerge at any time.

Anja Burkel

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