I am trying to determine the extent of transmission of Lassa fever through sexual contact. Any ideas how I can do this? I can analyze semen samples from areas that just witnessed Lassa fever outbreak in Nigeria for virus presence but obtaining these samples is near impossible. Analyzing semen samples submittted to tertiary health facilities for infertility investigation is a possibility, but wont be quite representative as Lassa is commoner in rural areas.
Also, I am at not sure how to measure transmission following sex and/or pregnancy, or adverse birth outcomes follow 'congenital Lassa' if it exists.
I think obtaining seminal fluid from Lassa fever patients will be quite difficult. However you can group patients into those in the incubation period (pre-pathogenic phase) Acutely ill persons (pathogenic Phase) and those convalescing (early post pathogenic phase) and those who have survived the illness (Post-pathogenic phase) This will enable us to know the stage at which Lassa fever is transmitted if it is actually sexually transmitted disease. That Lassa fever is transmitted through body fluids implies that it is very likely to be found in the semen except the blood testis barrier is capable of preventing Lassa fever virus from escaping into the seminiferous tubules. Even at that most of the seminal fluid is derived from seminal vesicles (60%), prostate gland (30%) and bulbo-urethral glands(5%) leaving 5% for the sperm cells..
This study will be easier to carry out in a center where there are several Lassa fever patients. Semen can easily be obtained when patients are seen in the clinic (because it becomes a requirement for evaluation), when they are being admitted ( if they are not acutely ill) when they are convalescing, and when they are being discharged. The patients must sign informed consent form. It will be almost impossible to obtain semen when they acutely ill.
However if the virus is found in the semen from the groups mentioned above it can safely be deduced that the the semen is present in the acute phase of the disease.
Thanks for the contribution. It has been established that Lassa fever virus is shed in urine for 3-9 weeks and in semen for up to 3 months following acute illness. For this reason, I am wondering if those that survived the acute illness pass the virus to their partners and if the partners become symptomatic, or if there are any adverse pregnancy outcomes from conception via a Lassa infested semen. i.e. does it cross placental barrier? do new born babies have Lassa antibodies in their blood at birth? any birth defects etc. but as you mentioned it is also important to know the prevalence of the virus in semen by disease stage, although this might not have huge public health import.
Hello Kolawole, I'm interested in many of the same questions and trying to understand how this shapes the immune response or how the adaptive immune response may affect severity of sequelae and viral shedding post hospital discharge. We have been working in Sierra Leone for some time but the sporadic nature of cases and low survival rates are hampering this line of questions. We are hoping to work with a couple groups in Nigeria where, as you mentioned, there are a lot more cases.
That said, I would be very surprised if the virus was passed on sexually for several reasons. Person-to-person spread is very rare except in hospital settings. People that recover from Lassa tend to how low libidos due to symptoms of sequelae. I would be more interested to see if the sexual partners of male survivors seroconvert (not necessarily have actual symptoms). In some areas of Sierra Leone, up to 50% of people from certain towns are seropositive for Lassa despite having no documented illness suggesting that people may be exposed often (via rodents or less likely through sexual transmission) but do not get sick enough to be hospitalized. I would be happy to talk to you about this and see if we have complimentary research interests.
Brian
Hello Brian, Thanks for your response and your insight is truly interesting. May I know which research institute you are working with in Sierra Leone and if you are aware of the Coalition for Epidemic Preparedness Innovation is coordinating efforts towards a large multi-country epidemiology studies to answer some of these pertinent questions?
Hi Kolawole, our research partners in Sierra Leone is the Lassa Program at the Kenema Government Hospital. We are part of a broader group called the Viral Hemorrhagic Fever Consortium made up of researchers from several US and African institutions which often collaborates together on projects. I am aware of CEPI ... some of the researchers I know are working with them or are applying for their grants.
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