Evaluation of Pediatric HIV Postexposure Prophylaxis Guideline Following Child Sexual Assault in Western Australia

BACKGROUND

HIV postexposure prophylaxis (PEP) following child sexual assault (CSA) is recommended in select cases. High rates of poor adherence to PEP are reported. We evaluated adherence to the recommended management of children following CSA at the tertiary pediatric facility in Western Australia and compared our approach with international guidelines.

METHODS

Medical records were reviewed for all children <16 years old assessed at Perth Children's Hospital between October 1, 2016 and November 30, 2020 following alleged CSA. Data, including exposure type, PEP adherence and follow-up, were collected. A review of contemporary national and international PEP guidelines was undertaken in parallel.

RESULTS

There were 511 alleged CSA events over the study period; 62/511 (12%) were appropriately risk-assessed as requiring PEP by the treating clinician. PEP was not prescribed in 8/62 (13%) events, with a reason documented for 6/8 (75%). Overall, less than half of children who were eligible for PEP were adherent to the 28-day regimen (23/54, 43%). Gastrointestinal upset contributed to early cessation in 5/54 (9%). Final 3-month blood-borne virus serology results were available in less than one in 3 children. A review of international clinical practice revealed significant heterogeneity of criteria for the provision of PEP and a paucity of pediatric-specific data.

CONCLUSIONS

We identified several areas of our PEP management that required strengthening, with limited direction available in current international guidelines. We have adopted a broader use of fixed drug combinations and implemented a multifaceted follow-up program. It will be essential to review the impact of these changes.

Presumptive neural microsporidiosis in a young adult German Shepherd dog from rural Australia

CASE REPORT

A 1-year-old, neutered male German Shepherd was presented with a 5-month history of episodic lethargy, intermittent fever, weight loss and a hunched posture. The dog was diagnosed with presumptive microsporidian meningoencephalitis based on cytological findings on cerebrospinal fluid analysis and a positive PCR test. The dog initially responded favourably to a 4-week course of trimethoprim-sulfadiazine, pyrimethamine and fenbendazole, and remained well for 12 weeks following cessation of treatment. Disease then recurred, and despite an initial positive response to treatment, he deteriorated and was euthanased 11 weeks later, 7.5 months after definitive diagnosis and 13 months after clinical signs were first reported.

CONCLUSION

To the authors knowledge, this is the first case of canine microsporidiosis in Australia.

Admixture on the northern front: population genomics of range expansion in the white-footed mouse (Peromyscus leucopus) and secondary contact with the deer mouse (Peromyscus maniculatus)

Range expansion has genetic consequences expected to result in differentiated wave-front populations with low genetic variation and potentially introgression from a local species. The northern expansion of Peromyscus leucopus in southern Quebec provides an opportunity to test these predictions using population genomic tools. Our results show evidence of recent and post-glacial expansion. Genome-wide variation in P. leucopus indicates two post-glacial lineages are separated by the St. Lawrence River, with a more recent divergence of populations isolated by the Richelieu River. In two of three transects we documented northern populations with low diversity in at least one genetic measure, although most relationships were not significant. Consistent with bottlenecks and allele surfing during northward expansion, we document a northern-most population with low nucleotide diversity, divergent allele frequencies and the most private alleles, and observed heterozygosity indicates outcrossing. Ancestry proportions revealed putative hybrids of P. leucopus and P. maniculatus. A formal test for gene flow confirmed secondary contact, showing that a reticulate population phylogeny between P. maniculatus and P. leucopus was a better fit to the data than a bifurcating model without gene flow. Thus, we provide the first genomic evidence of gene flow between this pair of species in natural populations. Understanding the evolutionary consequences of secondary contact is an important conservation concern as climate-induced range expansions are expected to result in new hybrid zones between closely related species.

Spatial variation in the parasite communities and genomic structure of urban rats in New York City

Brown rats (Rattus norvegicus) are a globally distributed pest. Urban habitats can support large infestations of rats, posing a potential risk to public health from the parasites and pathogens they carry. Despite the potential influence of rodent-borne zoonotic diseases on human health, it is unclear how urban habitats affect the structure and transmission dynamics of ectoparasite and microbial communities (all referred to as "parasites" hereafter) among rat colonies. In this study, we use ecological data on parasites and genomic sequencing of their rat hosts to examine associations between spatial proximity, genetic relatedness and the parasite communities associated with 133 rats at five sites in sections of New York City with persistent rat infestations. We build on previous work showing that rats in New York carry a wide variety of parasites and report that these communities differ significantly among sites, even across small geographical distances. Ectoparasite community similarity was positively associated with geographical proximity; however, there was no general association between distance and microbial communities of rats. Sites with greater overall parasite diversity also had rats with greater infection levels and parasite species richness. Parasite community similarity among sites was not linked to genetic relatedness of rats, suggesting that these communities are not associated with genetic similarity among host individuals or host dispersal among sites. Discriminant analysis identified site-specific associations of several parasite species, suggesting that the presence of some species within parasite communities may allow researchers to determine the sites of origin for newly sampled rats. The results of our study help clarify the roles that colony structure and geographical proximity play in determining the ecology of R. norvegicus as a significant urban reservoir of zoonotic diseases. Our study also highlights the spatial variation present in urban rat parasite communities, indicating that rats across New York City are not reservoirs for a homogenous set of parasites and pathogens. As a result, the epidemiological risks may be similarly heterogeneous for people in urban habitats.

Epidemiological investigation of grass seed foreign body-related disease in dogs of the Riverina District of rural Australia

OBJECTIVE

To characterise disease presentations caused by grass seed foreign body-related disease (GSFBD) in dogs, identify predisposing risk factors and suggest effective prevention strategies.

METHODS

A retrospective, case-control, telephone survey was conducted to obtain information on GSFBD in dogs from the Riverina district of New South Wales (NSW). Additionally, retrospective case records were obtained from Wagga Wagga Veterinary Hospital and Charles Sturt University Veterinary Teaching Hospital over the period July 2006 to October 2011. Signalment, history, investigative strategies, location and severity of lesion(s), cost of therapy, length of hospitalisation, recurrence rate and microbiology data were recorded.

RESULTS

Cases (473 dogs) meeting stringent inclusion criteria were identified. GSFBD comprised 2.0% of hospital presentations. Breeds with high-density coats were overrepresented. Otitis externa was the most common manifestation of GSFBD in the general practice (47%). In the referral practice pyothorax was the most common entity (34%). In both practices the range of clinical manifestations was broad, including a small number of dogs with catastrophic intracranial disease. Univariable and multivariable logistic regression analyses demonstrated dogs with GSFBD had 3-fold greater odds of having medium coats than short coats and 5-fold less odds of being groomed.

CONCLUSIONS AND CLINICAL RELEVANCE

Grass seeds are a major cause of disease in the dogs of south-west rural NSW, with presentations ranging from mild lameness to severe neurological disease. Some protection from GSFBD was achieved with frequent grooming. Clipping or coat searching without grooming was ineffective as a prevention strategy.

Nitrous oxide and vitamin B12 deficiency interact adversely on rat growth

The effects of vitamin B12 deprivation and exposure to nitrous oxide were studied in growing rats. A significant synergistic retardation of growth was seen in rats deprived of vitamin B12 and exposed to nitrous oxide for 90 minutes each day.