Host, season, habitat and climatic factors as drivers of Asian rodent tick (Ixodes granulatus) (Acari: Ixodidae) occurrence and abundance in Southeast Asia

The Asian rodent tick (Ixodes granulatus) occurs throughout much of Asia, it frequently bites humans, and zoonotic pathogens, such as Borrelia burgdorferi (sensu lato) and Rickettsia honei, have been detected within it. Unfortunately, the ecology of I. granulatus remains poorly known, including drivers of its abundance and the interaction ecology with its sylvatic hosts. To elucidate the ecology of this medically important species, the habitat preferences of I. granulatus were assessed in Singapore and Malaysia. Ixodes granulatus showed strong associations with old forest habitats, though across different age classes of old forest there was limited variation in abundance. Ixodes granulatus was absent from other habitats including young forest, scrubland, and parks/gardens. Within its sylvatic rodent hosts, a range of factors were found to be statistically significant predictors of I. granulatus load and/or infestation risk, including sex and body condition index. Male rodents were significantly more likely to be infested and to have higher loads than females, similarly, animals with a lower body condition index were significantly more likely to be infested. Proactive public health efforts targeted at preventing bites by this tick should carefully consider its ecology to minimise ecological overlap between humans and I. granulatus.

Phage typing set for differentiating Staphylococcus epidermidis

A phage typing set composed of 13 phages is described for characterizing Staphylococcus epidermidis. Isolates (372) from cases of bovine mastitis were used in this study. Of these, 350 or 94% were successfully delineated, and 63 phage types were observed. Twenty two cultures were not typeable.

Reduced set of phages for typing Escherichia coli

A phage typing set composed of 32 phages is described for differentiating Escherichia coli. Eight hundred sixty-six isolates from cases of bovine mastitis were used in this effort. Of these cultures 829, or 96%, were characterized successfully, and 178 phage types were observed. Thirty-seven isolates were not typable.

Mathematical immunogenetics I. Mathematics as language

This paper summarizes approaches to developing mathematics that can act as a language for immunogenetics. The need for this has been documented by showing inadequacies of the standard symbolism. Apparent distinctions in symbolizing and conceptualizing factors involved in immunogenetics are seen to disappear in the mathematical models presented here. One model, a three-fold Boolean matrix factorization, subsumes all approaches to the idea of specificity and yet is general enough to incorporate data beyond that found only in a reaction matrix.

Mathematical immunogenetics II. Antibody incidence structure

Mathematical Immunogenetics I argued for the development of mathematics as a language for immunogenetics. A three-fold factorization of a reaction matrix was seen to be the important form of a model of a first order immunogenetic system. In the present paper, results of the authors on determining this factorization are reworked from a physical perspective and presented in an algorithmic form that can be used to compute a labeling matrix from data. Computer programs to perform these computations are in preparation.

Reduced set of phages for typing salmonellae

A set composed of 27 phages is described for differentiating Salmonella spp. representative of groups A, B, C1, C2, D1, D2, E1, E2, E3, E4, G1, K, and N. All of the 1,245 cultures used in this effort were typable and were differentiated on the basis of the 420 phage patterns observed. All results were reproducible. Characteristic phage patterns were produced by a variety of Salmonella serovars isolated from campus incidents and a number of hospital, family, restaurant, and processing plant outbreaks to indicate an existing epidemiological relationship.