View list of archived news items.

57th Annual Meeting of the American Society for Tropical Medicine and Hygiene, New Orleans, LA, December 7-11, 2008

Dr.Siobhan Mor of InForMID attended the 57th Annual Meeting of the ASTMH and delivered two oral presentations.

Mor SM, Tumwine JK, Ndeezi G, Maheswari GS, Kaddu-Mulindwa D, Tzipori S, Griffiths JK. Respiratory cryptosporidiosis in Ugandan children

Abstract:
Respiratory infection with Cryptosporidium is recognized as a late-stage complication of intestinal cryptosporidiosis in HIV/AIDS patients. Respiratory signs and symptoms are also common in otherwise healthy adults and children with intestinal cryptosporidiosis, suggesting that respiratory infection may be more universal than currently accepted. We will present the preliminary findings of the first comprehensive study on respiratory cryptosporidiosis. We recruited children aged 9-36 months presenting with diarrhea to Mulago Hospital in Kampala, Uganda. Children with Cryptosporidium-positive and -negative stools (ratio 4:1) were selected for further evaluation, including sputum induction (in those with cough or unexplained respiratory signs) and collection of saliva and blood. Sputum samples were subjected to comprehensive microbiological testing, and both sputum and saliva were tested for Cryptosporidium by nested-PCR. To date, fecal samples from 641 children have been screened for Cryptosporidium, of which 92 (14.4%) were positive. Cough or other respiratory signs were present in 77.1% of stool-positive children, compared to 70.1% of stool-negative children (p=0.167). Of 45 sputum samples evaluated, 13 (28.9%) were positive for Cryptosporidium, all of which were collected from stool-positive children. Parasite DNA was only detected in 1/77 (1.3%) saliva samples (p<0.001). The relative absence of Cryptosporidium in saliva suggests that the existence of parasites in sputum reflects genuine respiratory tract infection rather than oral contamination during specimen collection. Of the 13 children with confirmed respiratory cryptosporidiosis, only 2 had other bacterial respiratory infections and all were HIV negative. These findings are novel and suggestive of an under-appreciated site of infection that may have important implications given the potential for respiratory transmission. We will discuss the possibility that Cryptosporidium contributes to respiratory disease in some children, in addition to the well-recognized outcomes of diarrhea and malnutrition.

Mor SM, Naumova EN, Tumwine JK, Tzipori S.  Temporospatial determinants of cryptosporidiosis in Ugandan children.  Oral presentation at the 57th Annual Meeting of the American Society for Tropical Medicine and Hygiene, New Orleans, Dec 2008

Abstract:
Transmission of cryptosporidiosis is believed to occur through two major pathways, one exclusively involving humans (C. hominis) and one involving humans and animals (C. parvum). Species identity is often used in epidemiological studies as a proxy for route of exposure. However, the need for molecular methods to differentiate between species often dictates that studies in resource poor areas be located in urban referral hospitals, where rural populations are underrepresented. Accordingly, we hypothesized that C. hominis and C. parvum may display unique temporal and spatial patterns, which are not revealed when data is aggregated at the hospital level. GIS and time series techniques were applied to a large database of children attending Mulago Hospital in Kampala, Uganda (n = 2778, n with cryptosporidiosis = 476). We explored whether the prevalence of cryptosporidiosis and the distribution of each species was related to various factors including population density, land use activities and heavy rainfall. While C. hominis was the dominant species in all regions studied, considerable heterogeneity existed in the prevalence of cryptosporidiosis and in Cryptosporidium species by area of residence. Preliminary findings revealed that children living in the more rural, sparsely populated District of Luwero were 3.7 times more likely to be infected with C. parvum compared to children residing in the urban Kampala District (p=0.039). C. hominis and C. parvum did not display a high degree of correlation in time, suggesting that the environmental drivers for transmission may be asynchronous. This study highlights how molecular and environmental data can be combined to gain a more complete knowledge of cryptosporidiosis transmission in specific populations.