Prevalence and Correlates of Cryptosporidium Infections in Kenyan Children With Diarrhea and Their Primary Caregivers

BACKGROUND

Cryptosporidium is a leading cause of diarrhea in Sub-Saharan Africa and is associated with substantial morbidity and mortality in young children.

METHODS

  We analyzed data from children aged 6-71 months presenting to 2 public hospitals in Western Kenya with acute diarrhea and their primary caregivers, including detection of Cryptosporidium by quantitative polymerase chain reaction (PCR) and immunoassay analysis in stool samples from both children and their caregivers. Associations between potential transmission sources and child/caregiver Cryptosporidium infection were evaluated using prevalence ratios (PRs). Secondary analyses evaluated host and clinical risk factors of child/caregiver Cryptosporidium infection.

RESULTS

Among 243 child-caregiver pairs enrolled, 77 children (32%) and 57 caregivers (23%) had Cryptosporidium identified by either immunoassay or PCR. Twenty-six of the 243 child-caregiver pairs (11%) had concordant detection of Cryptosporidium. Cryptosporidium infection in children was associated with detection of Cryptosporidium in caregivers (adjusted PR [aPR], 1.8; 95% CI, 1.2 to 2.6; P = .002) and unprotected water source (aPR, 2.0; 95% CI, 1.3 to 3.2; P = .003). Risk factors for Cryptosporidium detection in caregivers included child Cryptosporidium infection (aPR, 2.0; 95% CI, 1.3 to 3.0; P = .002) as well as cow (aPR, 3.1; 95% CI, 1.4 to 7.0; P = .02) and other livestock ownership (aPR, 2.6; 95% CI, 1.1 to 6.3; P = .03) vs no livestock ownership. Recent diarrhea in caregivers and children was independently associated with child and caregiver Cryptosporidium infections, respectively.

CONCLUSIONS

Our results are consistent with the hypothesis that Cryptosporidium transmission can occur directly between child-caregiver dyads as well as through other pathways involving water and livestock. Additional research into caregivers as a source of childhood Cryptosporidium infection is warranted.

Biochemical Screening of Five Protein Kinases from Plasmodium falciparum against 14,000 Cell-Active Compounds

In 2010 the identities of thousands of anti-Plasmodium compounds were released publicly to facilitate malaria drug development. Understanding these compounds' mechanisms of action--i.e., the specific molecular targets by which they kill the parasite--would further facilitate the drug development process. Given that kinases are promising anti-malaria targets, we screened ~14,000 cell-active compounds for activity against five different protein kinases. Collections of cell-active compounds from GlaxoSmithKline (the ~13,000-compound Tres Cantos Antimalarial Set, or TCAMS), St. Jude Children's Research Hospital (260 compounds), and the Medicines for Malaria Venture (the 400-compound Malaria Box) were screened in biochemical assays of Plasmodium falciparum calcium-dependent protein kinases 1 and 4 (CDPK1 and CDPK4), mitogen-associated protein kinase 2 (MAPK2/MAP2), protein kinase 6 (PK6), and protein kinase 7 (PK7). Novel potent inhibitors (IC50 < 1 μM) were discovered for three of the kinases: CDPK1, CDPK4, and PK6. The PK6 inhibitors are the most potent yet discovered for this enzyme and deserve further scrutiny. Additionally, kinome-wide competition assays revealed a compound that inhibits CDPK4 with few effects on ~150 human kinases, and several related compounds that inhibit CDPK1 and CDPK4 yet have limited cytotoxicity to human (HepG2) cells. Our data suggest that inhibiting multiple Plasmodium kinase targets without harming human cells is challenging but feasible.