Human botulism in Canada (1919-1973)

Since 1919, in Canada, 62 authenticated outbreaks of human botulism have affected 181 persons, with 83 deaths, a fatality rate of 46%. Among these, 41 outbreaks were bacteriologically determined (31 in one laboratory) as six type A, four type B, one both A and B, and 30 type E. About two thirds of the total outbreaks, cases and deaths involved Eskimos and Pacific coast Indians consuming raw marine mammal products and salmon eggs, respectively. Other parts of Canada recorded seven occurrences due to miscellaneous vehicles, three being type B. Since January 1961 there have been 38 outbreaks, involving 94 cases with 33 deaths. These include 18 outbreaks among Eskimos, affecting 51 persons (of whom 24 died) in Labrador, southern Baffin Island, northern Quebec, and the Mackenzie area. Also, putrid salmon eggs caused 15 outbreaks among Pacific coast Indians, totalling 35 cases, of whom only six died, the low fatality rate reflecting the introduction of type E botulinus antitoxin during 1961.

Occurrence of the metacercariae of Cotylurus erraticus (Rudolphi, 1809) Szidat, 1928 (Digenea: Strigeidae) in brown trout Salmo trutta L., and rainbow trout S. gairdneri Richardson, 1836, from Hanningfield Reservoir, Essex

Brown and rainbow trout from Hanningf?eld Reservoir, Essex and rainbow trout from associated raceways were found to be infected with the metacercariae of Cotyluriis erraticus throughout 1968. Both o brown and rainbow trout of age 2+ introduced into the reservoir in the spring became heavily infected with C. erraticus during their first summer in the reservoir. Rainbow trout were more heavily infected than brown trout. Infection increased with age in rainbow trout but this was not apparent in brown trout. The metacercariae are almost completely restricted to the pericardial cavity of the trout. The life-cycle of C. erraticus in Hanningfield possibly involves gulls as final hosts and the gastropod Valvata piscinalis as first intermediate host. C. erraticus has probably been introduced into the reservoir in infected trout from outside sources, or by infected avian final hosts.

DNA polymerase of murine sarcoma-leukemia virus: lack of detectable RNase H and low activity with viral RNA and natural DNA templates

Kirsten murine sarcoma-leukemia virus (Ki-MSV[MLV]) was found to contain less RNase H per unit of viral DNA polymerase than avian Rous sarcoma virus (RSV). Upon purification by chromatography on Sephadex G-200 and subsequent glycerol gradient sedimentation the avian DNA polymerase was obtained in association with a constant amount of RNase H. By contrast, equally purified DNA polymerase of Ki-MSV(MLV) and Moloney [Mo-MSV(MLV)] lacked detectable RNase H if assayed with two homopolymer and phage fd DNA-RNA hybrids as substrates. On the basis of picomoles of nucleotides turned over, the ratio of RNase H to purified avian DNA polymerase was 1:20 and that of RNase H to purified murine DNA polymerase ranged between <1:2,800 and 5,000. Based on the same activity with poly (A).oligo(dT) the activity of the murine DNA polymerase was 6 to 60 times lower than that of the avian enzyme with denatured salmon DNA template or with avian or murine viral RNA templates assayed under various conditions (native, heat-dissociated, with or without oligo(dT) and oligo(dC) and at different template enzyme ratios). The template activities of Ki-MSV(MLV) RNA and RSV RNA were enhanced uniformly by oligo(dT) but oligo(dC) was much less efficient in enhancing the activity of MSV(MLV) RNA than that of RSV RNA. It was concluded that the purified DNA polymerase of Ki-MSV(MLV) differs from that of Rous sarcoma virus in its lack of detectable RNase H and in its low capacity to transcribe viral RNA and denatured salmon DNA. Some aspects of these results are discussed.

Occurrence of Bunodera luciopercae (Digenea: Allocreadiidae) in fish from Hanningfield Reservoir, Essex

Perch, ruffe, brown trout and ten-spined stickleback from Hanningfield Reservoir, Essex were found to be infected withBunodera luciopercaein 1968–1969. Only perch were heavily infected.B. luciopercaeshowed an annual cycle of occurrence and maturation in perch. Mean intensity of infection with B.luciopercaeincreased to a maximum in perch 15–19.9 cms in length but decreased in larger and older fish. There was a significant positive association between the presence ofB. luciopercaeand that of the cestodeProteocephalus percaein perch, with both parasites occurring together more often than expected from chance alone.

Heme proteins: quantum yield determined by the pulse method

We report results of the application of the "pulse method" to the study of photodissociation of various ligands from several heme proteins. By use of this technique, which allows the determination of the quantum yield of photodissociation accurately and rapidly, several ligands (CO, O(2), isocyanides) have been investigated for sperm-whale myoglobin and trout hemoglobin I. In agreement with previous results, the new data lead to the conclusion that no simple relationship exists between the quantum yield and the affinity constant in the ground state. For trout hemoglobin I, the experiments were extended to measure the quantum yield of the CO photodissociation as a function of the initial degree of saturation, from fully saturated down to the initial values of about 1.5%. The results yield additional information to that obtained by the "steady-state" method, and in particular exclude the idea that the photochemical yield is in any way dependent on the fractional saturation of the molecule with carbon monoxide.