1. Superspreaders
Ferriell Henry

2. Superspreader: a person who infects disproportionally more secondary contacts than others infected with the same virus or bacteria.
20/80 Rule: 20% of infected individuals within a population are thought to be responsible for 80% of transmission capable by the pathogen.
About 10% of those infected will become new superspreaders.

3. How to become a superspreader?
> Experiment on mice done by Lass et al.
>Said that super-spreading might occur by someone who is co-infected with multiple parasites.
>Checked to see if mice co-infected with a microparasite (respiratory bacterium Bordetella bronchiseptica) and macroparsite (gastrointestinal helminth Heligmosomoides polygyrus) created superspreaders.
>Found that the treatment groups had half the bacterial load and egg output produced than the experimental group.

4. Becoming a superspreader continued...
>Decreased immunity = greater load of infection
>Individuals infected with many parasites who can infect multiple different hosts = central individuals
>Zoonotic diseases
>Infection by viruses with high mutation rate, like RNA viruses

5. Is thought to be a superspreader of typhoid fever
Typhoid Mary
Is thought to be a superspreader of typhoid fever
>Infected 50+ people over 7 year span while being asymptomatic herself.
> Was she infected with a helminth parasite at the same time?
>Her normal flora may have kept her asymptomatic, promoting superspreader activity.

6. Common diseases with epidemiology that require superspreaders
>HIV
>SARS
>measles
>malaria
>smallpox
>pneumonic plague
>TB
>Staphylococcus aureus
>typhoid fever

7. West Nile Virus >Zoonotic disease >Central individual = Mosquito
> Mosquito infects many species with West Nile Virus

8. A Change in Immune State
>Experiment by Gopinath et. al. with mice
>Superspreaders shown to have a similar gene expression to those of newly infected individuals.
>T cell expression is decreased while neutrophil expression is increased.
Antibodies are not being made but the pathogen load is controlled by the neutrophils.

9. Schistosomiasis >According to Rollinson et al.
>Large percentage of Schistosomiasis spread by “superspreaders”
-superspreader = someone who infects a disproportionate amount of people due to lack of cleanliness and being unreceptive to health education and treatment.
-Cambodia given annual treatments for past 8 years to treat for S. mekongi with coverage between 62% and 86%.
- Yet still cannot get control of disease.
- Children getting treatment but about 40% do not attend school.
- The relatively few people infected with immense amounts of schistosome parasites, seem to keep infecting/reinfecting their communities very quickly and in large amounts.

10. How to Prevent the occurrence of superspreaders
>Prevention of zoonotic diseases
>If it is a co-infection, try and locate/remove helminth
>Find a way to increase production of T cells

11. Sources http://en.wikipedia.org/wiki/Super-spreader
Gomez, J. M., et al. (2013). “Centrality in primate-parasite networks reveals the potential for the transmission of emerging infectious diseases to humans”. PNAS Early Edition. (1-4).
Gopinath, S., et al. (2013). The Systemic Immune State of Super-shedder Mice Is Characterized by a Unique Neutrophil-dependent Blunting of TH1 Responses. PLOS. DOI: /journal.ppat