Updates
September 1, 2014 5 minutes read
Updates
By Carol A. Kemper, MD, FACP
TB in domestic cats
Cases of TB in domestic cats and cat-to-human transmission: risk to public very low. https://www.gov.uk/government/news
A rare thing - TB in cats. We’ve heard of cattle, deer, elk, and elephants at the zoo and in a famous "Doc Marten" episode badgers in the U.K. as a source for human infection. But feline TB is fairly uncommon.
Public Health England (PHE) and Animal Health and Veterinary Laboratories Agency (AHVLA) investigated a cluster of TB infection in domestic cats in 2013. Initially, a single veterinarian identified the illness in 9 very ill cats from households within a few miles of each other near Newbury. The infection proved to be due to Mycobacterium bovis — and indeed, investigation of a nearby herd of cattle revealed a small number of animals with active infection with the same strain of M. bovis. Thirty-nine people with cat contact were offered testing; only 24 of whom accepted — 2 had active TB. Molecular analysis confirmed the strains were identical to the cat strains. Two additional people were found to have latent TB infection (unclear whether cat-related).
The PHE commented that M. bovis is responsible for fewer than 40 human cases of TB per year in the U.K., most of which are related to livestock exposure or occur in elderly people with a remote history of raw milk exposure. It is illegal to sell unpasteurized milk products in the U.K. But could someone have fed it to the cats?
A snap shot of HIV in the U.S.
Centers for Disease Control and Prevention. Behavioral and clinical characteristics of persons receiving medical care for HIV infection Medical Monitoring Project, United States, 2009. MMWR 2014;63(ss05):1-22.
By the end of 2009, 864,748 persons were living with HIV in the United States. While the U.S. HIV surveillance programs track basic demographic information about these cases, the Medical Monitoring Project, which is a national, cross-sectional surveillance project, collects much more intensive clinical and behavioral information on a subset of randomly selected participants. Study participants complete a detailed questionnaire and physicians provide abstracted chart data.
From January to April 2009, 421,186 HIV-positive adults > 18 years of age presented for outpatient care in the U.S. Of these, 9,338 subjects were selected from 461 participating sites (we were one of them); 4,217 patients completed the questionnaire and formed the basis for this report. While the detailed data is provided in the lengthy report, several points standout:
• 71% were male
• 50% identified as heterosexual and 50% as GBLT
• Three-fourths were > 40 yrs of age; and 54% had been HIV+ for 10 or more years;
• 44% were living below the poverty line and 9% were homeless;
• 81% had some kind of health coverage, including Medicaid (40%), Medicare (26%), or private insurance (30.6%)
• 68% had been diagnosed with AIDS; 87% had CD4 counts > 200 cell/mL within the previous 6 months;
• 88% were currently prescribed antiviral therapy; 6% had never been prescribed antivirals and the remainder had been treated but stopped therapy for various reasons.
• 72% had an undetectable HIV viral load < 200 copies/mL within the previous 6 months;
• 42% were current smokers;
• Alcohol use was common; half drank alcohol within the previous 3 months with an average of 3.1 drinks per day;
• 27% used non-injectable drugs, including marijuana (22%), crack (5%), cocaine (5%); and a much smaller number (2.1%) used injectable drugs;
• 25% of the female patients had been pregnant at least once since testing HIV+.
Indigenous Hepatitis E in the U.K.
Ijaz, s, et al. Indigenous Hepatitis E in England and Wales from 2003 to 2012: Evidence of an emerging novel phylotype of viruses. JID 2014; 209:1212-1218.
Given a rise in cases of Hepatitis E virus (HEV) infection in England and Wales the past 10 years, many of which appeared unrelated to international travel, Public Health England (PHE) has amped up efforts to improve surveillance testing and molecular characterization of HEV. In 2010, two PHE reference laboratories changed the assays used for antibody detection. And they began doing viral load testing, with PCR amplification and genotyping of isolates. In order to examined the relatedness of cases and identify clusters, a phylogenetic tree was created.
Between 2003 and 2012, 2713 cases of HEV were identified within England and Wales; of these, 51% were believed to be indigenous and unrelated to travel activity. Peaks of HEV infection occurred in 2005 (n = 329) and again, beginning in 2010- 2012, with up to 579 cases reported in 2012, 71% of which were believed to be indigenous. Analysis indicated this was not the result of heightened awareness and an increase in the number of samples being submitted to the laboratories.
Genotypic analysis confirmed that most of the travel-related cases were due to genotype 1 (G1) infections, mainly from the Indian subcontinent, whereas all of the indigenous isolates were Genotype 3 viruses. Of these G3 viruses, 215 of 229 isolates (94%) from 2003-2009 were group 1 and 6% were group 2. But from 2010-2012, there was a decided shift, with emergence of group 2 viruses in 58% of cases. Clearly the spike in indigenous cases observed from 2010-2012 coincided with the appearance of these newer viruses. Sequencing and phylogenetic analysis revealed the emergence of newer group 2 subtype viruses - seen only after 2010.
In conclusion, molecular analysis demonstrated that two distinct and somewhat overlapping low-level indigenous outbreaks were occurring in England and Wales during this 10 year period, with the emergence of novel group 2 subtypes during the past 3 years.
Demographic data failed to point to a clustering of cases, as would be observed with a food-borne outbreak. The question remains, where did these novel HEV genotype 3 subtype viruses come from? Two theories are actively being investigated, including the possibility that one or more individuals with chronic immunosuppression, which can result in chronic HEV infection, could excrete low levels of the organism in the environment. In addition, there is some evidence that HEV viruses can infect pigs, although no direct link has been established. HEV infection can become established in countries not previously thought endemic for this infection.
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