the immunological basis for disease dilution

The Immunological Basis for Disease Dilution

Sheena WheelerDr. Anna Jolles

•Many human diseases are transmitted from non-human animals (Zoonotic diseases)

•Some species are better at transmitting diseases than others

•Biodiversity is important to ecosystem services

RELEVANCE

BACKGROUNDDisease Dilution: Empirical Findings

high biodiversity = reduced risk of disease low biodiversity = increased risk of disease

Sin Nombre Virus in Deer Mice (Laurie J. Dizney)

BACKGROUND

BIODIVERSITY =

= DISEASE

Why is the deer mouse good at transmitting disease?

HYPOTHESIS

We hypothesize that short-lived species invest less in certain aspects of their immune system, which may make them better at transmitting diseases.

Ex: VS.

MY OBJECTIVE

To examine the immune differences between short-lived and long-lived rodent species

METHODS: FIELD

1. Trap different rodent species throughout Oregon (Sherman and Tomahawk traps)

2. Collect blood, feces, and ectoparasites from each rodent

3. Ear tag, measure, weigh and release

TRAPPING LOCATIONS1. Local

2. Rogue River-Siskiyou National Forest

3. Willamette National Forest

4. Steens Mountain Eastern OR

MY OBJECTIVE

To examine the immune differences between short-lived and long-lived rodent species

1.Determine the differences in white blood cell composition between rodent species.

BACKGROUNDWhite blood cells (WBC): travel in bloodstream to infected areas and destroy responsible bacteria

Complete Blood Count:• Determine numbers and types of white

blood cells (WBC) in an animalGood general way to see how the immune system of an animal functions

WBC BACTERIA

METHODS: LAB1. Perform complete blood counts (CBC) on each

rodent:A) White blood cell counts

B) Cell differentiation

Lymphocyte Neutrophil Band Monocyte Eosinophil Basophil

MY OBJECTIVE

Examine the immune differences between short-lived and long-lived rodent species

1.Determine the differences in blood cell composition between rodent species.

2.Evaluate the health of different rodent species via fecal parasite analysis.

METHODS: LAB1. Fecal Float to examine the types of parasite eggs

2. Fecal McMasters to count the different parasite eggs within the feces

PICTURES

PRELIMINARY RESULTS

Table 1: Average and standard deviation of total white blood cells/μl for six species of rodents.

1. Complete Blood Counts

Species Sample Size Average WBC/μl St. Dev. WBC

California Ground Squirrel 10 10234.57 6270.63

Chipmunk 3 8666.67Dusky Footed Woodrat 9 8812.5 2863.89

Norway Rat 8 3581.11 3821.13

Black Rat 2 9527.78 2710.58

Deer Mouse 79 3488.48 2360.07

PRELIMINARY RESULTS

Table 2: Percent of species with fecal parasites and percent of each type of parasite in each species.

2. Fecal Analysis

Species Sample SizeFecal Parasites Coccidia Capillaria Other

California Ground Squirrel 10 80.00% 80.00% 10.00% 70.00%Chipmunk 3 100% 100% 0% 0%

Dusky Footed Woodrat 9 100.00% 100.00% 75.00% 0.00%Norway Rat 8 50.00% 67.00% 33.00% 0.00%Deer Mouse 79 25.53% 21.28% 0.00% 0.02%

Pinyon Mouse 4 100.00% 33.00% 0.00% 67.00%

WHAT’S NEXT?• Continue data collection of rodents around

Oregon

• Trap larger/longer lived rodents (beaver, nutria)

• Analyze data

ACKNOWLEDGEMENTS Howard Hughes Medical Institute (HHMI)

Undergraduate Research, Innovation, Scholarship and Creativity(URISC)

Dr. Anna Jolles

Dr. Rhea Hanselmann

Dr. Kevin Ahern