My previously healthy patient developed a viral illness with fever and headache few days after swimming in a community pool. Can swimming pools be a source of viral infection?

Yes! Swimming pools have been implicated in the transmission of a variety of pathogens,  including enteric viruses (eg, echovirus, coxackie virus, hepatitis A virus, norovirus) which account for nearly one-half of all swimming pool-related outbreaks.  Adenoviruses also account for a significant number of swimming pool outbreaks.1,2

The most commonly reported symptoms in swimming pool outbreaks have been gastroenteritis, respiratory symptoms and conjunctivitis. However, aseptic meningitis and hepatitis may also occur. 1

Because viruses cannot replicate in the environment outside of host tissues, their presence in swimming pool is the result of direct contamination by those in the water who may shed viruses through unintentional fecal release or through body fluids, such as saliva, mucus, or vomitus.  The finding of E. coli in 58% of pool water samples in 1 CDC study suggests the presence of stool as a primary source of infection.3

On average, each person has 0.14 grams (range 0.1 gram to 10 grams) of fecal material on their perianal surface that could rinse into the water if pre-swim shower with soap is omitted.4-5 Coupled with the potential for inadequate disinfection or chlorination of pool water, it is not surprising that swimming pools may serve as a source of infection.  

CDC recommends keeping feces and urine out of the water, checking the chlorine level and pH before getting into the water and not swallowing the water you swim in.3 

Bonus pearl: Did you know that pool water has also been associated with Cryptosporidium and Giardia and waterslides with E.coli-0157 outbreaks?

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References

  1. Bonadonna L, La Rosa G. A review and update on waterborne viral diseases associated with swimming pools. Int j Environ Res Public Health 2019;16, 166. Doi:10.3390/ijerph16020166. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6352248/
  2. Keswick BH, Gebra CP, Goyal SM. Occurrence of enteroviruses in community swimming pools. Am J Public Health 1981;71:1026030. https://www.ncbi.nlm.nih.gov/pubmed/6267950
  3. CDC.Microbes in pool filter backwash as evidence of the need for improved swimmer hygiene—Metro-Atlanta, Georgia, 2012. MMWR 2013;62:385-88. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6219a3.htm
  4. Gerba CP. Assessment of enteric pathogen shedding by bathers during recreational activity and its impact on water quality. Quant Microbiol 2000; 2:55-68 https://arizona.pure.elsevier.com/en/publications/assessment-of-enteric-pathogen-shedding-by-bathers-during-recreat
  5. CDC. Model Aquatic Health Code. 8.0 Annexes: fecal/vomit/blood contamination response Annex (6.0 policies and management), 2008. https://www.cdc.gov/healthywater/pdf/swimming/pools/mahc/structure-content/mahc-fecal-vomit-blood-contamination-response-annex.pdf
  6. CDC. Surveillance of waterborne disease outbreaks and other health events associated with recreational water—United States, 2007-2008 and surveillance of waterborne disease outbreaks associated with drinking water—United States, 2007-2008. MMWR 2011;60. 1-76. https://www.ncbi.nlm.nih.gov/pubmed/21937976

 

 

My previously healthy patient developed a viral illness with fever and headache few days after swimming in a community pool. Can swimming pools be a source of viral infection?

My patient with acute onset headache, photophobia, and neck stiffness does not have CSF pleocytosis. Could she still have meningitis?

Although the clinical diagnosis of meningitis is often supported by the presence of abnormal number of WBCs in the CSF (AKA pleocytosis), meningitis may be present despite its absence.

Among viral causes of meningitis in adults, enteroviruses are associated with lower CSF WBC count compared to herpes simplex and varicella zoster, with some patients (~10%) having 0-2 WBC’s/mm31,2.  Of interest, among children, parechovirus (formerly echovirus 22 and 23) meningitis is characterized by normal CSF findings3.

Though uncommon, bacterial meningitis without CSF pleocytosis has been reported among non-neutropenic adults,  including Neisseria meningitidis, Streptococcus pneumoniae, Hemophilus influenzae, Listeria monocytogenes, E. coli, and Proteus mirabilis4A European study also reported normal CSF WBC in nearly 10% of patients with Lyme neuroborreliosis (including meningitis) caused primarily by Borrelia garinii5.

Cryptococcal meninigitis may also be associated with normal CSF profile in 25% of patients with HIV infection6.

 

References

  1. Ihekwaba UK, Kudesia G, McKendrick MW. Clinical features of viral meningitis in adult:significant differences in cerebrospinal fluid findings among herpes simplex virus, varicella zoster virus, and enterovirus infections. Clin Infect Dis 2008;47:783-9. https://www.ncbi.nlm.nih.gov/pubmed/18680414
  2. Dawood N, Desjobert E, Lumley J et al. Confirmed viral meningitis with normal CSF findings. BMJ Case Rep 2014. Doi:10.1136/bcr-2014-203733. http://casereports.bmj.com/content/2014/bcr-2014-203733.abstract
  3. Wolthers KC, Benschop KSM, Schinkel J, et al. Human parechovirus as an important viral cause of sepsis like illness and meningitis in young children. Clin Infect Dis 2008;47:358-63. https://www.ncbi.nlm.nih.gov/pubmed/18558876
  4. Hase R, Hosokawa N, Yaegashi M, et al. Bacterial meningitis in the absence of cerebrospinal fluid pleocytosis: A case report and review of the literature. Can J Infect Dis Med Microbiol 2014;25:249:51. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4211346/pdf/idmm-25-249.pdf
  5. Ogrinc K, Lotric-Furlan S, Maraspin  V, et al. Suspected early Lyme neuroborreliosis in patients with erythema migrans. Clin Infect Dis 2013; 57:501-9. https://www.ncbi.nlm.nih.gov/pubmed?term=23667259
  6. Darras-Joly C, Chevret S, Wolff M, et al. Cryptococcus neoformans infection in France: epidemiologic features of and early prognostic parameters for 76 patients who were infected with human immunodeficiency virus. Clin Infect Dis 1996;23:369-76. https://oup.silverchair-cdn.com/oup/backfile/Content_public/Journal/cid/23/2/10.1093/clinids/23.2.369/2/23-2-369.pdf?Expires=1501035620&Signature=FhHMHUHAMmT3rz4ld8QAMet-weu-BWgm5YR6nA4jjSGVGIeaVlMNPgeOkW2fniiel54HQhIs1Kkp3PpzT1glxhJeZvQiGXQCSOoF-jS1SK7S~kBb-oHs4qsIJzN0OJxNAXfoJi4bl7OeKaLTyIE3P8~slwH0BBi7RncSYVgVR4NkOnFpYgn27~wY7pDSUNWvzGFKoSeYGeM0TsAqna-QmXzodITB5bgr1mO6Q6OGUxCsqRwhr6xNb~4G93oqRcsO19gyUluCE0xYt0KbKWuQxJeh8AbtJkNrS08~XInMR50bQZOUb80j0~dtg9jRTGzXQaDllVByoX2Alr48hlhogw__&Key-Pair-Id=APKAIUCZBIA4LVPAVW3Q
My patient with acute onset headache, photophobia, and neck stiffness does not have CSF pleocytosis. Could she still have meningitis?