Breast Milk vs. Hepatitis C: Breast Milk Wins

An interesting paper published in the Journal of Infectious Diseases details the discovery that human breast milk has antiviral activity against the hepatitis C virus (HCV). 

Approximately 5-10% of deliveries by HCV positive women result in perinatal transmission of HCV to the child. Transmission is related to HCV viremia, HIV co-infection, prolonged membrane rupture, and intrapartum exposure to maternal blood. Breast milk, though it contains the virus, is not thought to be a major risk.

This paper adds further weight to the safety of HCV positive mothers breastfeeding their children. In this study, researchers incubated HCV--at concentrations 1000x higher than that found in breast milk--with breast milk from HCV uninfected women. Infectivity after incubation with breast milk was reduced 2-3 fold for all genotypes of the virus. Further experimentation confirmed that the mechanism underlying the antiviral effect was due to free fatty acids that disrupt the viral envelope (see graphic).

In an accompanying editorial, Ravi Jhaveri of UNC writes: "After reading this article, when we clinicians next encounter an HCV-infected patient that just delivered a healthy infant and wants to breastfeed, we have yet another reason to say 'Breast is Best'."

Elite HIV Controllers: The Exceptions that Prove a Cure is Possible?

Today I saw a patient who was infected with HIV in the 1970s and is alive today. In the modern era of HIV treatment in the US, seeing people survive long term with HIV is commonplace. In fact, it is projected that in a few years individuals over 50 will comprise half the cases in the US (as I was quoted saying in this article).

The interesting thing about this patient, however, is that the patient remains alive without the benefit of drugs. HIV has been held at bay by the patient's immune system. The patient is what we refer to as a long-term non-progressor. These individuals exhibit no overt signs of immune destruction by HIV despite years of infection.

The terminology defining long-term non-progressors can get confusing as they are divided into one of two types:

1. Elite controllers: no measurable virus detected using routine test
2. Viremic controllers: viral loads < 2000 copies/mL

The patient I saw today is an elite controller, with no measurable virus in the blood. 

Studying the mysteries of how elite controllers control HIV replication is thought to be key to developing a cure (see great graphic from amFAR) for HIV. Most current hypothesis are currently focused on what immune responses are operative in these patients (it is not thought that the HIV virus is defective in these patients nor the CD4 cells immune from infection). 

Disproportionate pneumonic cases in Madagascar plague outbreak

The African island nation of Madagascar is reporting an outbreak of plague which has infected 86 people, killing 39. The more deadly--and contagious--pneumonic form of the disease represents 90% of cases.

Madagascar is a well known focus of plague and has recently led the world in cases. Madagascar is also the site where a naturally occuring multi-drug resistant strain of plague was discovered.

The United States reports a few cases per year, the great majority of which are of the bubonic form. These cases are almost exclusively from the western half of the country as the rodent populations which serve as the reservoir for the plague bacillus (Yersinia pestis) seem not to move east of an artificial plague line which falls roughly on the 100th meridian. 

A few months ago, when a squirrel in Los Angeles County tested positive for plague, I was interviewed by Erin Burnett on CNN on this topic.

What is most interesting about the current cases in Madagascar is that they are of the pneumonic form and not the much more common bubonic form. It is crucial to understand the reason behind the disproportionate number of the pneumonic cases.

Botulism aka "sausage fever" in Texas

Coincidentally on the same day that I delivered a lecture on various bioterrorism topics, four cases of botulism were reported in Amarillo, Texas. During my lecture, I reminded the audience that botulism was once known as "sausage fever", provoking snickering in the crowd.

Remembering that botulus is the Latin word for sausage helps reinforce the fact that many botulism cases in the US are food-borne, often linked to home-canned substances (as these cases will likely turn out to be). Learning several important pieces of information regarding the  4 cases, who are all known to each other and 3 of whom have household contact, will be essential. Answers to the following questions will be crucial in the investigation:

• Has confirmatory testing been done?
• Is the same toxin type responsible in all cases? 
• Why did only 2 of the 4 meet criteria for antitoxin administration?

Another recently reported development with botulism was the discovery of a new of an 8th toxin type, for which no anti-toxin is currently available.

Dengue Fever: Back in the USA?

There has recently been an uptick in media reports focused on the threat of the mosquito-borne dengue virus in the US. The latest is an article, in which I am quoted, that details the mosquito control efforts of California, a state where no cases have been detected. 

Until this year, local spread of dengue was know to have occurred in Texas (chiefly along the border with Mexico), Florida, and Hawaii, the details of which can be found in a paper my colleagues and I wrote on the topic. This year, however, in addition to the uncovering of evidence of local spread in Houston, a locally-acquired case was detected in New York.

The key thing to remember with respect to dengue is that since the Aedes mosquito is present over a large swath of the US and there are a continual stream of potentially infected travelers--who may be asymptomatic--it is not surprising to find instances of local spread of dengue occurring in the US. In fact, serosurveys along the Texas-Mexico border have shown up to 40% of individuals exhibit evidence of exposure to dengue. 

Clinicians and public health officials should keep these facts in mind when investigating or treating unexplained febrile illnesses.