• Dr. Nicole Vumbaco | DVM

Routes of Transmission:

Updated: Nov 29, 2021

Routes of transmission have traditionally been classified as vector-borne (ie-biting insects like fleas, sand flies or human lice), or secondary to a cat bite or scratch, typically associated with the presence of fleas. Over the last few decades, additional routes of transmission have been discovered.

Below are helpful publications discussing newly discovered routes of potential transmission.

The research is evolving and much more is needed but implicate the following:

  1. Animal Saliva

  2. Perinatal Transmission

  3. A growing list of newly identified vectors, like ticks

  4. Needle Stick Transmission in a Veterinarian

  5. Blood Transfusions (Bartonella remains viable during long-term storage of Red Blood Cell Units)

Animal Saliva-Cat Bite Transmission:

  1. Bartonella henselae Antibodies after Cat Bite. Emerging Infectious Disease, 2008

  2. Detection of Bartonella henselae in domestic cats' saliva. Iranian Journal of Microbiology, 2010

  3. Isolation of Bartonella quintana from a woman and a cat following putative bite transmission. Journal of clinical microbiology, 2006

  4. Cat Scratch Disease and Arthropod Vectors: More to it than a Scratch? Journal of the American Board of Family Medicine, 2010

Perinatal Transmission:

Sadly, transplacental transmission of Bartonella species occurs commonly in naturally and experimentally infected rodents. Compounding data suggests that Bartonella can undergo vertical transmission in humans.

In general, 'Vertical Transmission' means that an infection/pathogen uses the intimate nature of pregnancy to transmit disease directly from mother to- an embryo, fetus, during childbirth or to the baby during pregnancy. Vertical Transmission typically occurs when the mother has a pre-existing disease or becomes infected during pregnancy.

During pregnancy, an infection with Bartonellosis has often been related to serious maternal or fetal complications (including miscarriage, fetal death, or premature delivery. It has also brought into question transmission via breastfeeding. This reinforces the need for early detection and treatment of infected pregnant women. Bartonella has a slew of symptoms and co-morbidities in children, many of which are neuropsychiatric. I have only started to brush the surface of this data and it is very unsettling, especially for someone who wants to have children but is currently infected with Bartonellosis.

  1. Molecular Evidence of Perinatal Transmission of Bartonella vinsonii subsp. berkhoffii and Bartonella henselae to a Child. Journal of Clinical Microbiology, 2010

  2. Possible Vertical Transmission of Bartonella bacilliformis in Peru. The American Journal of Tropical Medicine and Hygeine, 2015

New Vectors:

  1. Potential for Tick-borne Bartonelloses. Emerging Infectious Disease, 2010: ** “Since the submission of this manuscript, we found 3 cases of B. henselae infection transmitted by Dermacentor spp. Ticks”**

  2. Identification of Novel Zoonotic Activity of Bartonella spp., France. Emerging Infectious Disease, 2016

  3. Case Reports Suggest Spiders, Red Ants, Kissing Bugs and Mites are capable of potential transmission" Galaxy Diagnostics Suspected Insect and Arthropod Vectors for Bartonella, 2019.

Needle Stick Transmission in Veterinarians

  1. Suspected Needle Stick Transmission of Bartonella vinsonii subspecies berkhoffii to a Veterinarian. Journal of Veterinary Internal Medicine, 2010

  2. Unknown Fever and Back Pain Caused by Bartonella henselae in a Veterinarian After a Needle Puncture: A Case Report and Literature Review. Vector-Borne and Zoonotic Diseases, 2011

Transfusion Transmission:

Bartonella can cause a chronic, sub-clinical infection, sometimes without any symptoms. That makes it possible for someone with Bartonella (despite displaying minimal or no symptoms) to readily donate if they feel healthy. Bartonella can survive long-term in multiple types of blood products. Bartonella's profile typically evades direct PCR detection thus the safety of the blood (in regards to Bartonella) cannot be guaranteed by standard screening performed on blood products.

If you are a Bartonella or Lyme patient, or someone suffering from Vector-borne disease, the recommendation is to not donate blood or be an organ donor. Transmission by blood transfusion has been well established in animal models involving mice.

"It is important to highlight the presence of asymptomatic people, who account for about 45% of the population in some endemic areas; consequently, the risk of transfusion transmission is of note, especially because of the ability of B. bacilliformis to survive in blood stored at 4 ºC for up to 1 year"- [Citing Article]

  1. Bartonella henselae survives after the storage period of red blood cell units: is it transmissible by transfusion? Journal of Transfusion Medicine, 2008

  2. Infectious agents, Leptospira spp. and Bartonella spp., in blood donors from Cajamarca, Peru. Journal of Blood Transfusion, 2016

  3. Long time survival of Bartonella bacilliformis in blood stored at 4 °C. A risk for blood transfusions. Journal of Blood Transfusion, 2012

  4. Bartonellosis as cause of death after red blood cell unit transfusion. Ultrastructural Pathology, 2009

  5. CHART of Pathogens transmitted in red blood cell transfusions: An up-to-date table (listing viruses, bacteria, protozoa and prions) Baylor University Medical Center, 2018

Webinar: Bartonelloses: Vectors and other modes of transmission

1.0 CME. This module provides an overview of key vectors and modes of transmission associated with Bartonella spp. infection, with special attention to ongoing debates surrounding tick transmission, perinatal transmission, and other modes, like transfusion and needlesticks.


Recent Posts

See All
  • Facebook
  • Vumbaco PT Page
  • Instagram
  • Published Veterinary Articles
  • Nicole Vumbaco Photography
  • GoFundMe