IgG and IgM antibodies to chlamydial species were measured by a microimmunofluorescence method by using elementary bodies of Chlamydia pneumoniae Kajaani 7 and Chlamydia trachomatis 1. These antibody assays have been successfully used in the etiological diagnosis of pneumonia in children both in industrialized and developing countries 28 , Mycoplasma IgM antibodies from the second serum samples taken on day 21 were measured with a commercial kit Platelia; Sanofi Diagnostics Pasteur S.
Rhinovirus was found in patients The percentage of rhinoviruses was the same in both males and females. Coronaviruses were the second most common group of causative agents and were detected in 17 patients by serology. In addition to the 80 patients culture-positive for rhinoviruses, 11 nasopharyngeal-aspirate samples were positive by virus culture. Three cases of influenza A were detected by serology only, whereas the other seven patients were positive by antigen detection, culture, or serology.
For the other respiratory viruses, five patients remained negative by culture or antigen detection but paired serum antibodies showed a rise. In addition, coronaviruses were detected by serology only. Taken together, virus culture was positive for the respiratory viruses in 91 cases Evidence of a double viral infection was found in 10 patients.
Of these patients, three had both rhinovirus and coronavirus OC43, two had rhinovirus and influenza A virus, two had rhinovirus and parainfluenza virus type 2, one had rhinovirus and adenovirus, one had rhinovirus and influenza B virus, and one had rhinovirus and enterovirus infections.
Adenoviruses were endemic. Infection was diagnosed at the Department of Virology, Turku University, with specimens derived mainly from pediatric patients. Serological assays suggested bacterial infections in seven patients. Of these, four patients had a rise in IgG antibodies against C. One patient had a rise in antibodies against Streptococcus pneumoniae , one patient had a rise in antibodies against both H. None of the patients had beta-hemolytic group A Streptococcus in their nasopharynges.
One patient had acute otitis media and was treated with antibiotics. This patient had a serological rise in antibodies against H. Three patients received antibiotics for urinary tract infections, and one patient received antibiotics for prophylaxis after a dental operation during days 7 to With the exception of these five patients, all recovered uneventfully without antibiotics, including those patients with a serological indication of bacterial infection.
Surprisingly, there have been no recent investigations using modern virological techniques lasting long enough to cover several virus outbreaks. We recruited patients for 10 months. This period included outbreaks of five different respiratory viruses Fig. Patients were not admitted to the study during June, July, and August, which are summer holiday months in Finland and in which only a few respiratory infections occur.
This study shows that in addition to virus culture, serology and PCR techniques are needed to detect the maximal number of infections. This observation agrees with earlier studies with adults 14 , For children, virus antigen detection is often the method of choice 12 , Virus antigen tests are sensitive for RSV and adenoviruses, which are common in young children but rare in adults, as seen also in this study 12 , Another factor contributing to the low yield of antigen-positive samples may be that adults shed less virus than children 8 , Rhinoviruses were the causative agent of the common cold in half of the cases in this investigation.
Although rhinoviruses are the most common cause of the common cold, it must be stressed that almost half of the cases are caused by other viruses.
We detected rhinoviruses, RSVs, influenza A viruses, adenoviruses, and parainfluenza type 3 viruses circulating in the community at the same time Fig. These infections are often clinically indistinguishable in adults.
This observation emphasizes the need to identify the specific virus in studies of specific antivirals. We studied bacterial cultures performed with nasopharyngeal samples for beta-hemolytic streptococci and serologic responses for five additional bacteria.
Interestingly, we found serological evidence of concomitant bacterial infection in seven patients. One of them, with H. The other patients, with infections with S. Recently, Kaiser et al. In these patients, antibiotic treatment shortened the duration of symptoms compared to the duration for culture-negative patients.
Even those common-cold patients who may have bacterial coinfection seem to recover uneventfully without antibiotic treatment.
Radiologically confirmed sinusitis is part of the normal clinical course of the common cold 9. Amoxicillin did not influence the clinical course of rhinosinusitis These findings agree with earlier studies showing that antibiotic treatment of the common cold is not beneficial. This treatment policy results in problems not only with the cost but, even more importantly, also with emerging antibiotic resistance of bacteria. An Icelandic study showed an obvious association of antibiotic use in the community with the prevalence of penicillin-resistant pneumococci 2.
Even though we used a large battery of diagnostic tests, there are some limitations to our study. By using the best available cell line for each virus, it would be possible to reach an even higher yield of virus-positive cultures.
Moreover, PCR techniques are often more sensitive than the conventional virus culture method for detection of microbes and PCR could be used for other viruses as well. In routine clinical practice, there is no need to do etiological diagnosis of the common cold. The implications of this study, nevertheless, are clear.
The common cold is a viral illness for which the etiology can be shown in most cases. Bacterial coinfections are very rare. Antibiotic treatment is not necessary in otherwise healthy young adults with common colds. We thank Matti Waris for providing data on virus infections in the community and for preparation of the graph. A fungus gets nutrition from plants, food, and animals in damp, warm environments. Many fungal infections, such as athlete's foot and yeast infections , are not dangerous in a healthy person.
People with weak immune systems from diseases like HIV or cancer , though, may get more serious fungal infections. Protozoa pro-toe-ZO-uh are one-celled organisms, like bacteria. But they are bigger than bacteria and contain a nucleus and other cell structures, making them more like plant and animal cells.
Protozoa love moisture. So intestinal infections and other diseases they cause, like amebiasis and giardiasis , often spread through contaminated water. Some protozoa are parasites. This means they need to live on or in another organism like an animal or plant to survive. For example, the protozoa that causes malaria grows inside red blood cells, eventually destroying them.
Some protozoa are encapsulated in cysts, which help them live outside the human body and in harsh environments for long periods of time. Germs: Bacteria, Viruses, Fungi, and Protozoa. Researchers have identified more than foodborne diseases. Most of them are infections, caused by a variety of bacteria, viruses, and parasites.
Harmful toxins and chemicals also can contaminate foods and cause foodborne illness. Clostridium botulinum botulism Listeria Escherichia coli E. Food Safety Tips. More Information. Get Email Updates. What's this? Links with this icon indicate that you are leaving the CDC website. Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
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