Eosinophils rise in response to hookworm infection, seeming to peak between weeks 3-10. This study describes that eosiniphils peak between days 38-64 :

http://www.ajtmh.org/cgi/content/abstract/37/1/126

Peaks between weeks 3-9:

http://www.ajtmh.org/cgi/content/full/75/5/914#F5

Starts to be elevated at days 14-21, peaked on day 42 and declined to
a persistently elevated level:

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1809522

Peaked week 5, declined by week 20:
“In the CD cohort, blood eosinophilia developed from week 5 (mean
2.60×109/l (1.89) v week 1 0.18×109/l (0.10) v week 20 0.59 (0.20)). ”

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1856386

But my favorite study, the MS study in Argentina, where they tracked 12 MS patients already infected with helminths and compared them to 12 other MS patients over a 4.6 year period, only recruited the helminth infected patients if their eosinophelia was high, (800-1800 mm3) and it stayed that way for the duration of the study. Their quantitative egg counts were also high: between 1,180 and 9,340 eggs/gram.

Eosinophils reflect parasitic infection, and the higher the number, usually the larger the worm burden. One indication that one has lost their worm infection would be having an elevated EOS for an extended length of time, then having it fall to baseline. Obviously, stool tests would confirm this, as well as symptom regression. In the dose-ranging trial, the higher doses resulted in higher EOS counts, though they did not test longer than 12 weeks.

I only tested my EOS at baseline and 18 weeks, so I never tracked a rise and fall. Baseline values were 74 cells/mcL and only rose to 192 post infection. (Normal is 15-550). Remember, I added worms from weeks 10-18, which may have provoked an immune response that curtailed the new worms from attaching, and possibly displaced some of the first 10, like this capsule endoscopy study shows. So by week 18, perhaps I had very few worms…

I will be testing EOS at weeks 3, 6, 9, and 12 to see how they respond to 10 larvae. I don’t think 10 hookworms are going to be enough to cause persistent eosinophilia. And like the MS study, it seems important to get and maintain a large enough worm burden to stimulate eosinophilia, and maintain a higher egg count. I’m very curious what my results will be this time…

http://www.ncbi.nlm.nih.gov/pubmed/16824566

“Time delays between patient and laboratory selectively affect accuracy of helminth diagnosis.

London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.

Studies of intestinal helminth infections are influenced by the constraints of sample collection, as identification of helminth ova in stools is affected by the time since evacuation from the host. Different methods may be required to optimise diagnostic sensitivity under different study conditions. In the context of studies in rural Malawi, we collected stool samples with different time delays from production by subjects to sample collection by field staff, to examination in the laboratory. Stools were processed by Kato-Katz (KK) or formol-ether concentration (FEC) methods. Hookworm and Schistosoma mansoni were the most common helminths identified. The prevalence of hookworm was higher with KK (270/988, 27%) than with FEC (191/988, 19%). Comparison was made between the results from the two methods according to the timing of the processing steps. Delays in processing did not affect retrieval of S. mansoni. A decrease in sensitivity of almost 50% for detection of hookworm was observed with either method when preservation/refrigeration was delayed by more than 3h. A delay of 1 day from refrigeration or preservation to laboratory processing also reduced the sensitivity for hookworm by 50% for both methods. Care must be taken in studies of multiple helminth infections owing to the selective reduction of hookworm ova during transport. This is particularly critical when samples are not preserved, even over short periods of time, and even with formalin preservation.”