Gastrointestinal Infections Influenza Miranda de Graaf 28 May 2018 [email protected] Viroscience lab, Erasmus MC, Rotterdam, the Netherlands Gastrointestinal infections
. Worldwide 3-6 million children die each year from infectious gastroenteritis
. Gastrointestinal infections are viral, bacterial or parasitic infections that cause gastroenteritis, an inflammation of the gastrointestinal tract
. Symptoms include diarrhea, vomiting, and abdominal pain. Gastrointestinal infections
. Which viruses cause gastrointestinal infections . Host defences . Transmission via the fecal-oral route . Tracking transmission . Rotaviruses . Noroviruses . Role of Bacteria . Take home messages
Foodborne Illness (USA)
Estimated nr FB cases Estimated nr Estimated nr deaths Per 100000 hospitalisations
95% norovirus
95% norovirus
99% norovirus
Scallan et al., 2011 Gastrointestinal infections
. Norovirus Major outbreaks in children and adults
. Rotavirus Major cause of diarrhea in children and infants, Rotavirus is responsible for the most severe cases.
. Sapovirus Infects children and adults
. Astrovirus Infects mainly children <5 years
. Adenovirus Infects children much more often. Adenovirus can cause diarrhea. But the most common symptom is respiratory illness
Gastrointestinal infections Gastrointestinal infections
. Norovirus ssRNA positive strand virus, Non-enveloped . Sapovirus ssRNA positive strand virus, Non-enveloped . Rotavirus dsRNA virus, Non-enveloped . Astrovirus ssRNA positive strand virus, Non-enveloped . Adenovirus dsRNA virus, Non-enveloped . Entrovirus ssRNA positive strand virus, Non-enveloped
Gastrointestinal infections
. Norovirus Non-enveloped . Sapovirus Capsid viruses . Rotavirus . Astrovirus Naked viruses . Entrovirus Host defenses against gastrointestinal infections
. The acidity of the stomach (pH 1.5 to 3.5) inactivates acid labile viruses such as rhinoviruses . Bile salts can destroy the lipid envelopes of many viruses (mainly non-enveloped viruses infect the gastrointestinal tract) . Antiviral defences Proteolytic enzymes and secretory IgA
Host defenses against gastrointestinal infections
. Intestinal mucus . Gut motility . Normal intestinal flora (microbiome) . Immune mechanisms Phagocytic, humoral, cell mediated . Genetic determinants (presence of receptors)
Transmission via the fecal oral route
De Graaf et al., 2017 Transmission via the fecal oral route
Climate change
Fecal oral transmission Fecal oral trasmission Food handler Food production phase High incidence High incidence Human pathogens Human and animal pathogens End of chain Globalisation Local, endemic Mixed infections > risk Early in chain Norovirus, Hepatitis A Widespread
Norovirus, rotavirus,
Hepatitis A hepatitis E, enterovirus Transmission –tracking the virus Hepatitis A
. Pain areas: in the abdomen, joints, or muscles . Gastrointestinal: diarrhea, nausea, or vomiting . Whole body: fatigue, fever, or loss of appetite . Also common: dark urine, itching, weight loss, or yellow skin and eyes
Transmission –tracking the virus Hepatitis A
Problem for food investigation: Major challenge for people to remember what they ate 30 days ago Transmission –tracking the virus Hepatitis A
Institute de Veille Sanitaire http://www.invs.sante.fr/display/?doc=surveillance/hepatite_a/p oint_vha_020310.htm Transmission –tracking the virus Hepatitis A
International Network of Food Safety Authorities (INFOSAN) notification:
November 2009- Australian multi-jurisdictional outbreak of hepatitis A > 250 people linked to semi-dried tomatoes imported frozen tomatoes tested positive
Action: Alert posted on INFOSAN February 2010- France Outbreak of hepatitis A Semi-dried tomatoes were a possible vehicle
Transmission –Globalisation Transmission –Globalisation
Genetic profiles of enterovirus type 71 in different geographic regions
B0 B1 B2 C1 C1 Netherlands B2 C2 C2 C1 C1 UK C2 C2
Europe Austria C1 C4
Bulgaria B1 Hungary B1 Norway C1
USA B1 B2 C1 C2 C2
Australia B2 C1 B3 C2 B4 C4
Vietnam C1/C4/C5
China C3 C4
Singapore B3 Asian B4 Pacific region B3 Malaysia B4 B5/C1 C1
Japan B4 B4 C4 B2 C2 B5
Taiwan B2 C2/C3 B4 C4 B5 C5 1960 1970 1980 1990 2000 2010 Basics Rotavirus
Order: Unassigned Family: Reoviridae Genus: Rotavirus Species: Rotavirus A-I
Double stranded RNA genome Eight segments Inner and outer capsids
Basics Rotavirus Basics Rotavirus
. Severe gastroenteritis in children between 6 and 24 months . 2-day incubation period . 3-8 days watery diarrhea . Can cause chronic infections in immunocompromised patients . Fever and abdominal cramps are common
Rotavirus Pathology
Ciarlet et al., 2002 Rotavirus diarrhea
. Infections leads to shorting and atrophy of the villi
. Mature absorptive cells are replaced with immature cells
Ramig et al., 2004 Rotavirus diarrhea
. Immature cells have reduced capacity to absorb salt and water . Reduced capacity to absorb carbohydrates . NS4 functions as a enterotoxin . The enteric nervous system is activated
Ramig et al., 2004
Rotavirus Vaccination
. A vaccine is available . Started in 1980s with a “Jennerian” approach with a attenuated bovine rotavirus . Rotateq -bovine backbone, with human rotavirus glycoproteins . Rotarix -attenuated human rotavirus
Ramig et al., 2004 Rotavirus Vaccination
Gastañaduy et al., 2013 Basics Norovirus Basics
Order: Unassigned Family: Caliciviridae Genus: Norovirus Species: Norwalk
Norovirus Basics
. RNA virus, capsid, no lipids . Low infectious dose . High levels of shedding (up to 1011 viral copies/ml) . Very stable outside host . Little immunity, lasting short . Asymptomatic infections . Transmission via contact, food, water, droplets produced by vomiting (Larry)
. NO CULTURE MODEL UNTIL RECENTLY
ORF1 ORF3 Norovirus Replication p48 NTPase p22 VPg Pro RdRp VP2 3’ VPg AAAAAAAAAAAn NS1/2 NS3 NS4 NS5 NS6 NS7 VP1 N-term 2C-Like 3A-Like 3C-Like
Binding to histobloodgroup antigens 1. Atttachment (determine your bloodtype) 2. Internalisation
4. Translation 3. Uncoating and disassembly
VPg (+)vRNA VP2
VP1
p48 NTPase p22 VPg 3CLpro RdRp 6. Replication VPg (+)vRNA (-) vRNA 5. Post-translational cleavage
p48 p22
NTPase VPg RdRp (+)vRNA 3CLpro VP2 (-) vRNA
VP1
VPg genomic VPg vRNA 7. Encapsidation VPg
VPg subgenomic VPg vRNA VPg
8. Release De graaf et al., 2017 Diversity
De graaf et al., 2016 Norovirus -transmission and settings-
Food then person to person
Foodborne
Other
Person to person
Unknown
Waterborne Norovirus -transmission and settings-
Foodborne GI Person to Person GI
NoV I.1 NoV I.1 NoV I.2 NoV I.2 NoV I.3 NoV I.3 NoV I.4 NoV I.4 NoV I.5 NoV I.5 NoV I.6 NoV I.6
Foodborne GII Person to person GII
NoV II.1 NoV II.2 NoV II.3 NoV II.4 NoV II.5 NoV II.6 NoV II.7 Norovirus -transmission and settings-
Country (source) Samples analyzed % positive Reference China 128 19% NoV Kou et al., 2006 Netherlands 42 17% NoV Boxman et al., 2006 Italy 235 6% HAV, 14% NoV, 2 % both Groci et al., 2007 Italy 170 14% HAV Macaluso et al., 2006 Netherlands 64 22% EV Lodder et al., 2005 France 52 40% EV Dubois et al., 2004
Spain 60 47% AdV,19% EV, 24% HAV Muniain-Mujika et al., 2003
France, Netherlands, 87 9% NoV,5% EV Beuret et al., 2003 Ireland Spain ? 27% HAV, 44% EV Romalde et al., 2002
Italy 100 market 23% HAV Chironna et al., 2002
Italy 142 35% (13%) De Medici et al., 2001
France 108 17% AV, 23% NoV, 19% EV, 27% RV LeGyader et al., 2000
Brazil 27 22% HAV Coelho et al., 2003
South America 17 24% HAV Romalde et al., 2001 Norovirus Pathogenesis
Pathogenesis is not clear . Lesions in the small bowel Broadening and blunting of intestinal villa . Transient malabsorption of sugar and fats . Decreased activity in brush border enzymes Norovirus Tropism
Karst et al., 2016 Norovirus Tropism
Karst et al., 2015 Norovirus Tropism
. Enterocytes in biopsies of immunocompromised patients . Macrophages, Dendritic cells and B cells in mice (murine norovirus) . Cells in the lamina propria in chimpanzees (human norovirus) . Enterocytes in pigs (human norovirus) Norovirus culture model
A breakthrough in the norovirus field is the development of a cell culture system for testing the infectivity of norovirus
. Replication occurs in stem-cell derived human organoids (mini-gut) in enterocytes (Ettayebi et al, Science 2016, Karandikar et al J. Gen. Virol 2016)
. Successful replication of several norovirus strains
. In humans and the norovirus culture model susceptibility to norovirus infection is dependent on the expression histobloodgroup antigens
Norovirus culture model The influence of bacteria on enteric viruses Attachment factor
Karst et al., 2016 Attachment factor
Karst et al., 2016 Stability
The release of lipopolysaccharide by gram negative bacteria
Karst et al., 2016 -Immune modulation-
. Mouse norovirus can cause persistent infections
. Bacteria suppress antiviral IFNλ
. Without IFNλ there is viral persistence
Karst et al., 2016
Take home messages
. Gastrointestinal infections pose significant public health impact . Noroviruses most common foodborne disease . Fecal-oral transmission can occur via person-to-person, water and food, vomites . Globalisation of the food chain leads to globalisation of exposures and potential for large scale and diffuse outbreaks . The microbiome can play an important role in viral gastroenteritis
Questions????
Norovirus group -Nele Villabruna -Claudia Schapendonk -Mark de Jong
-Jeroen van Kampen -Annemiek van van der Eijk -Marion Koopmans