IN HUMANS continued
Cryptosporidiosis in Australia: (a) cryptosporidiosis notifications by year in Australia from 2010 to 2020 and (b) average number of cases per month during this period. Data from National Notifiable Diseases Surveillance System, accessed April 2021.
(a)
(b)
6,000
600
4,000
400
2,000
200
0
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
Month
Year
• There is no specific treatment. Supportive therapy, including fluid and electrolyte replacement and antimotility drugs, may be indicated. In the immunocompromised patient, the most effective treatment approach is to aid recovery of the patient’s immune status (e.g. anti-retroviral therapy) and/ or reduction in immunosuppressive therapy (transplantation patients). • Increasingly, human diagnostic laboratories are using combined Giardia/Cryptosporidium enzyme immunoassays and Cryptosporidium real-time PCRs for diagnosis. However, if microscopy is solely used for diagnosis, ensure that Cryptosporidium spp. is differentiated adequately from Cyclospora cayetanensis , as the latter responds to antimicrobials.
• Chronic severe enteritis which is unresponsive to treatment may be seen in immunocompromised individuals. Patients can have chronic diarrhoea that lasts for greater than two months, with shedding of oocysts throughout this time. Specific conditions associated with chronic disease include advanced HIV infection, immunosuppressive chemotherapy affecting cell-mediated immunity (including corticosteroids), organ transplantation and primary T cell immunodeficiencies. 6,15 • Extra-intestinal infection may be seen in immunocompromised patients, primarily from luminal extension to involve the biliary tree (resulting in biliary scarring) or pancreatic duct. 15 Disseminated infection is not common. • Untreated cryptosporidiosis in pregnant women can result in severe dehydration and diarrhoea, with the potential to negatively impact the foetus.
KEY CONSIDERATIONS 1. Most cases of cryptosporidiosis in humans are due to human host-adapted ( C. hominis ) or livestock adapted ( C. parvum ) species, however zoonotic infection with canine and feline adapted species ( C. canis and C. felis ) may rarely occur. 2. Cryptosporidiosis is more common in dogs and cats less than one year of age and is typically not associated with clinical signs. 3. Immunocompromised individuals at risk of significant disease associated with cryptosporidiosis should avoid adopting young or stray animals and minimise exposure to potentially contaminated faeces.
Prevention of cryptosporidiosis is dependent on good hygiene including hand washing (alcohol-based hand sanitisers do not effectively inactivate Cryptosporidium oocysts) and prompt removal and disposal of animal faecal matter.
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Companion Animal Zoonoses Guidelines 35
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