Archive for March, 2023

Molecular Detection of Bartonellosis

https://wwwnc.cdc.gov/eid/article/29/3/22-1223_article

Bartonella spp. Infections Identified by Molecular Methods, United States

David W. McCormick, Sara L. Rassoulian-Barrett, Daniel R. Hoogestraat, Stephen J. Salipante, Dhruba SenGupta, Elizabeth A. Dietrich, Brad T. Cookson, Grace E. Marx1Comments to Author , and Joshua A. Lieberman1
Author affiliations: Centers for Disease Control and Prevention, Fort Collins, Colorado, USA (D.W. McCormick, E.A. Dietrich, G.E. Marx); University of Washington, Seattle, Washington, USA (S.L. Rassoulian-Barrett, D.R. Hoogestraat, S.J. Salipante, D. SenGupta, B.T. Cookson, J.A. Lieberman)
March, 2023

Abstract

Molecular methods can enable rapid identification of Bartonella spp. infections, which are difficult to diagnose by using culture or serology. We analyzed clinical test results of PCR that targeted bacterial 16S rRNA hypervariable V1–V2 regions only or in parallel with PCR of Bartonella-specific ribC gene. We identified 430 clinical specimens infected with Bartonella spp. from 420 patients in the United States. Median patient age was 37 (range 1–79) years; 62% were male.

We identified:

  • B. henselae in 77%
  • B. quintana in 13%
  • B. clarridgeiae in 1%
  • B. vinsonii in 1%
  • B. washoensis in 1% of specimens
  • B. quintana was detected in 83% of cardiac specimens
  • B. henselae was detected in 34% of lymph node specimens

We detected novel or uncommon Bartonella spp. in 9 patients. Molecular diagnostic testing can identify Bartonella spp. infections, including uncommon and undescribed species, and might be particularly useful for patients who have culture-negative endocarditis or lymphadenitis.

______________

Currently, 12 species of Bartonella genus are associated with human infection, but that number is constantly changing. Because Bartonella spp. infections are not nationally notifiable diseases, there is limited knowledge of the epidemiology of this disease in the US.  In my experience it is prolific.

For more:

Category:

Bartonella, research, Testing

Study Examines Persistent Powassan in Mice

https://journals.asm.org/doi/10.1128/mbio.03606-22

Of Murines and Humans: Modeling Persistent Powassan Disease in C57BL/6 Mice

Authors: Stacey L. P. Scroggs, Danielle K. Offerdahl, Philip E. Stewart, Carl Shaia, Amanda J. Griffin, Marshall E. Bloommarshall.bloom@nih.gov
AUTHORS INFO & AFFILIATIONS
DOI: https://doi.org/10.1128/mbio.03606-22
Feb. 21, 2021
ABSTRACT
Powassan infection is caused by two closely related, tick-transmitted viruses of the genus Flavivirus (family Flaviviridae): Powassan virus lineage I (POWV) and lineage II (known as deer tick virus [DTV]). Infection is typically asymptomatic or mild but can progress to neuroinvasive disease. Approximately 10% of neuroinvasive cases are fatal, and half of the survivors experience long-term neurological sequelae. Understanding how these viruses cause long-term symptoms as well as the possible role of viral persistence is important for developing therapies.
We intraperitoneally inoculated 6-week-old C57BL/6 mice (50% female) with 103 focus-forming units (FFU) DTV and assayed for infectious virus, viral RNA, and inflammation during acute infection and 21, 56, and 84 days postinfection (dpi). Although most mice (86%) were viremic 3 dpi, only 21% of the mice were symptomatic and 83% recovered. Infectious virus was detected only in the brains of mice sampled during the acute infection. Viral RNA was detected in the brain until 84 dpi, but the magnitude decreased over time. Meningitis and encephalitis were visible in acute mice and from mice sampled at 21 dpi. Inflammation was observed until 56 dpi in the brain and 84 dpi in the spinal cord, albeit at low levels.
These results suggest that the long-term neurological symptoms associated with Powassan disease are likely caused by lingering viral RNA and chronic inflammation in the central nervous system rather than by a persistent, active viral infection. The C57BL/6 model of persistent Powassan mimics illness in humans and can be used to study the mechanisms of chronic disease.
_____________
For more:

Category:

Anaplasmosis, Viruses