In persons who are homozygous for the C282Y mutation, iron-overload-related disease developed in a substantial proportion of men but in a small proportion of women.

There are 11 different pathogenic trypanosomes in trypanosomiasis endemic regions of Africa. Their detection and characterisation by molecular methods relies on species-specific primers; consequently several PCR tests have to be made on each sample. Primers ITS1 CF and ITS1 BR, previously designed to amplify the internal transcribed spacer (ITS1) of rDNA, have been evaluated for use in a universal diagnostic test for all pathogenic trypanosomes. Blood was collected from 373 cattle and 185 camels. The primers gave constant PCR products with the stocks of each taxon tested. Members of subgenus Trypanozoon (T. brucei brucei, T. evansi, T. b. rhodesiense and T. b. gambiense) gave a constant product of approximately 480 bp; T. congolense, savannah 700 bp, T. congolense kilifi 620 bp and T. congolense forest 710 bp: T. simiae 400 bp, T. simiae tsavo 370 bp, T. godfreyi 300 bp and T. vivax 250 bp. The sensitivity of the test ranged from 10 pg for Trypanozoon, T. congolense clade and T. vivax to 100 pg for T. simiae and T. godfreyi. The primers detected cases of multi-taxa samples, although the sensitivity was reduced with an increase in the combinations. A better detection rate of trypanosome DNA was recorded with buffy coats than from direct blood. With the field samples, the diagnostic sensitivity was close to the sensitivity obtained using single reactions with species-specific primers for Trypanozoon 38/40 (95%) and T. congolense savannah 30/33 (90.9%) but was lower with T. vivax 25/31 (77.4%). The primers offer promise as a routine diagnostic tool through the use of a single PCR; however, further evaluation is recommended.

Sequence analysis of a polymerase chain reaction (PCR)-amplified 298-bp region of the Cryptosporidium parvum 18S rRNA gene was carried out on 10 human and 9 animal isolates. Eight of the 9 animal isolates and 3 human isolates displayed the recognition sequence TATATTT, whereas 7/10 human isolates exhibited the recognition sequence TTTTTTTTTTT. Sequence analysis of the ninth animal isolate, which was recovered from a Koala, revealed this isolate to be different from both human and animal isolates. The AT richness of the rDNA recognition sequences rendered them unsuitable for primer design and therefore a diagnostic randomly amplified polymorphic DNA fragment previously developed in our laboratory was also sequenced. Analysis of 2 human and 2 animal isolates again revealed distinct differences between animal and human isolates. On the basis of this sequence information, diagnostic primers were designed that could directly differentiate between animal and human isolates on the basis of the size of the PCR product. The ability to differentiate directly between human and animal isolates has important implications for studies of the transmission and zoonotic potential of this organism. These results also raise further doubts about the uniformity of the species C. parvum.

Many issues concerning the taxonomy of Echinococcus have been resolved in recent years with the application of molecular tools. However, the status of Echinococcus maintained in transmission cycles involving cervid intermediate hosts remains to be determined. The recent characterization of the parasite from cervids in Finland has highlighted the paucity of data available, particularly that from North America. In this study, we have characterized a large number of Echinococcus isolates from cervids from Western Canada on the basis of morphology and molecular genetic techniques. Our results support earlier studies suggesting that Echinococcus of cervid origin is phenotypically and genetically distinct to Echinococcus maintained in domestic host assemblages, and also confirms that Echinococcus of cervid origin does not constitute a genetically homogeneous group. However, our data do not support the existence of 2 distinct genotypes (strains/ subspecies) with separate geographical distributions. Our data appear to support the existence of only 1 species in cervids, but additional isolates from cervids and wolves in other endemic regions should be characterized before a final decision is made on the taxonomic status of Echinococcus in cervids.

The evidence that mutations in the HFE gene are associated with increased cancer risk is inconsistent. The Melbourne Collaborative Cohort Study is a prospective cohort study that commenced recruitment in 1990. Participants of born in Australia, New Zealand, the United Kingdom or Ireland (n = 28,509) were genotyped for the HFE C282Y variant. Incident cancers were ascertained from Australian cancer registries during an average of 14 years follow up. Hazard ratios, confidence intervals and p-values were obtained from separate Cox regression analyses for colorectal, breast and prostate cancers, all other solid cancers and all cancers. Compared with those with no C282Y variant, C282Y homozygotes were at increased risk of colorectal cancer (HR 2·28; 95% CI 1·22, 4·25; p = 0.01) and female C282Y homozygotes were at increased risk of developing breast cancer (HR 2·39; 95% CI 1·24, 4·61; p = 0.01) but male C282Y homozygotes were not at increased risk for prostate cancer (HR 0·96; 95% CI 0·43, 2·15; p = 0.92). C282Y/H63D compound heterozygotes were not at increased risk for colorectal cancer, (HR 1 27; 95% CI 0·80, 2·01); breast cancer, (HR 1·16; 95% CI 0·74, 1·84); or prostate cancer (HR 1·08; 95% CI 0·68, 1·70). Conclusion HFE C282Y homozygotes have twice the risk of colorectal and breast cancer compared with those without the C282Y variant.