{"id":73074,"date":"2026-04-17T08:14:33","date_gmt":"2026-04-17T08:14:33","guid":{"rendered":"https:\/\/christiancorner.us\/index.php\/2026\/04\/17\/hidden-viral-reservoirs-in-tonsils-may-explain-school-year-respiratory-outbreak\/"},"modified":"2026-04-17T08:15:09","modified_gmt":"2026-04-17T08:15:09","slug":"hidden-viral-reservoirs-in-tonsils-may-explain-school-year-respiratory-outbreak","status":"publish","type":"post","link":"https:\/\/christiancorner.us\/index.php\/2026\/04\/17\/hidden-viral-reservoirs-in-tonsils-may-explain-school-year-respiratory-outbreak\/","title":{"rendered":"Hidden viral reservoirs in tonsils may explain school-year respiratory outbreak"},"content":{"rendered":"\n
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A study conducted at the University of Sao Paulo (USP) in Brazil suggests that tissues such as tonsils and adenoids may serve as hiding places for rhinovirus, which causes the common cold and is responsible for the majority of respiratory infections worldwide.<\/p>\n

Using samples from 293 children who had surgery to remove these tissues, the study showed that the pathogen can infect immune cells known as lymphocytes and live there for a long time without causing symptoms. This allows the virus to potentially be transmitted to others without warning.<\/p>\n

“The virus has a ‘date’ with the child population. Every year, about two or three weeks after school starts in temperate regions, there is an outbreak of rhinovirus. And children pass it on to their parents and grandparents. We have always wondered: What does the start of school have to do with it? Well, children gather in closed spaces, and some of them having the virus in their throats can lead to an outbreak in the school, even if they have no symptoms,” Rhinovirologist comments Eurico de Arruda Neto, professor at the Ribeir\u00e3o Preto School of Medicine (FMRP-USP) and coordinator of the research, supported by FAPESP (projects 13\/06380-0, 13\/16349-2 and 17\/25654-4).<\/p>\n

As the researchers explain, it was already known that rhinovirus infects the epithelium (the outermost layer of the mucosa) of the nose and throat, hijacks the cellular machinery to multiply, and causes the host cell to rupture upon completion of this process, releasing progeny capable of causing new infections. For this reason, scientists consider it a lytic virus, which causes cell lysis or breakdown. This rapid and destructive cycle immediately attracts the attention of the immune system, which, in most cases, eliminates the virus from the body within about five to seven days.<\/p>\n

The major finding of the study was that rhinovirus can reach deeper layers of tonsil and adenoid tissues in addition to the epithelium. There, it can infect B lymphocytes, which produce antibodies, and CD4 T lymphocytes, which conduct the local immune response. These cells have a long lifespan and store the “memory” of the immune system. Instead of killing them, rhinovirus persists inside these cells for a long time, in the same situation as is seen with herpes viruses, HPV and cytomegalovirus.<\/p>\n

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The samples we analyzed were from children who had undergone surgery for snoring, sleep apnea, or recurrent infections related to tonsillar and adenoid hypertrophy. At the time of surgery, they had essentially no symptoms. “Nonetheless, we detected rhinovirus in a large number of participants.”<\/p>\n

Eurico de Arruda Neto, Professor, Ribeir\u00e3o Preto School of Medicine<\/p>\n<\/blockquote>\n

In addition to tonsils and adenoids, the children’s nasal secretions were also analyzed. According to data published in Medical Virology Journal<\/em>The virus was present in at least one of the three sites (tonsils, adenoids, or secretions) in 46% of the volunteers. Viral proteins and other characteristics that mimicked rhinovirus \u2013 and were therefore capable of infecting another person \u2013 were also seen in these tissues.<\/p>\n

The research was conducted in collaboration with Ronaldo Martins, a virologist at the Ribeir\u00e3o Preto School of Pharmaceutical Sciences (FCFRP-USP), as well as Vilma Anselmo-Lima, Edwin Tamashiro and Fabiana Valera, professors at the FMRP-USP.<\/p>\n

<\/p>\n

virus garden<\/h2>\n

In previous studies, Arruda’s team had detected adenovirus (another cause of the common cold), influenza A (flu), and SARS-CoV-2 (COVID-19) in samples of tonsils and adenoids from children who had surgery. The latter two are known to cause long-lasting infections in some patients. However, in the case of rhinovirus, it came as a surprise.<\/p>\n

“I think no matter what common virus we look for, we’ll find it. And not just in the tonsils and adenoids, but in other lymphoid tissues throughout the body, such as the lymph nodes. We already have some preliminary evidence that lymphoid tissues are a kind of ‘garden’ for the virus. And our hypothesis is that this is a good thing. It acts as a booster for immune memory, meaning that even long after the initial exposure Antibody production continues,” says Arruda.<\/p>\n

However, in the case of people suffering from asthma, this can be problematic. One hypothesis raised by the article’s authors is that infectious viruses in tonsil CD4 T lymphocytes may release inflammatory substances that act on the lungs and cause asthma attacks. It is already known that colds and flu are among the most common causes of asthma attacks, especially in young children.<\/p>\n

Additionally, a previous study by the group detected respiratory viruses in normal adenoids (without hypertrophy), which are located next to the Eustachian tube. This may explain why some children suffer from frequent otitis media.<\/p>\n

“This virus can travel from the adenoids to the middle ear and cause inflammation there. The child will not sneeze or cough, but the ear will swell, closing the narrow Eustachian tube and producing fluid in which the local bacterial flora begins to proliferate,” the researchers explain.<\/p>\n

clinical implications<\/h2>\n

Based on these findings, Arruda believes that pediatricians should be alert to the potential for diagnostic confusion regarding the causes of childhood illnesses.<\/p>\n

“For example, a child with hypertrophic tonsils comes to the emergency room with respiratory infections and bronchiolitis symptoms caused by respiratory syncytial virus, but the throat swab test detects rhinovirus from a previous infection. In other words, tests performed on secretions may not always reflect what is actually happening in the lungs,” the researchers say. “We have evidence that this viral persistence can occur even in people with normal-sized tonsils and adenoids.”<\/p>\n

Arruda says another hypothesis to be investigated is whether viruses that persist in lymphoid tissues could cause problems for immunosuppressed patients. “For example, patients undergoing bone marrow transplants often develop lung infections and bronchiolitis. Doctors, nurses and medical students are usually blamed for bringing the virus into high-risk wards. But could it be that the virus was already present in the patient’s tonsils or adenoids and has now reactivated due to reduced immunity? This does not necessarily have to be outside-in transmission. We have begun to investigate this in mice.”<\/p>\n

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Source:<\/p>\n

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Funda\u00e7\u00e3o de Amparo e Pesquisa do Estado de Sao Paulo<\/a><\/p>\n<\/div>\n

Journal Reference:<\/p>\n

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Martins, R., and others<\/em>. (2026) Rhinovirus infects B and CD4 T lymphocytes in hypertrophic tonsils in children. Medical Virology Journal<\/em>. doi:10.1002\/jmv.70809. https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/jmv.70809<\/a>.<\/p>\n<\/div>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"

A study conducted at the University of Sao Paulo (USP) in Brazil suggests that tissues such as tonsils and adenoids may serve as hiding places for rhinovirus, which causes the common cold and is responsible for the majority of respiratory infections worldwide. Using samples from 293 children who had surgery to remove these tissues, the<\/p>\n","protected":false},"author":1,"featured_media":73077,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[59],"tags":[7256,3677,1650,6821,22443,22442,22441,1261],"class_list":["post-73074","post","type-post","status-publish","format-standard","has-post-thumbnail","category-daily-bread","tag-explain","tag-hidden","tag-outbreak","tag-reservoirs","tag-respiratory","tag-schoolyear","tag-tonsils","tag-viral"],"_links":{"self":[{"href":"https:\/\/christiancorner.us\/index.php\/wp-json\/wp\/v2\/posts\/73074","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/christiancorner.us\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/christiancorner.us\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/christiancorner.us\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/christiancorner.us\/index.php\/wp-json\/wp\/v2\/comments?post=73074"}],"version-history":[{"count":1,"href":"https:\/\/christiancorner.us\/index.php\/wp-json\/wp\/v2\/posts\/73074\/revisions"}],"predecessor-version":[{"id":73078,"href":"https:\/\/christiancorner.us\/index.php\/wp-json\/wp\/v2\/posts\/73074\/revisions\/73078"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/christiancorner.us\/index.php\/wp-json\/wp\/v2\/media\/73077"}],"wp:attachment":[{"href":"https:\/\/christiancorner.us\/index.php\/wp-json\/wp\/v2\/media?parent=73074"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/christiancorner.us\/index.php\/wp-json\/wp\/v2\/categories?post=73074"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/christiancorner.us\/index.php\/wp-json\/wp\/v2\/tags?post=73074"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}