Future activities on rabies

Project Coordinator:
• Dr Cécile Troupin

Staff members:
Dr. Thonglakhone Xaybounsou
Longthor Vachouaxiong
Kedkeo Intavong

To be determined


Rabies is an invariably fatal viral zoonotic disease that represents a major public health concern in developing countries. Every year, an estimated 59,000 people die from rabies and approximately 80% of human cases occur in rural areas with over 40% of deaths afflicting children aged under 15 years. In Asia, the estimated number of deaths per year is around 38 000. The reality might largely exceed these figures because of poor diagnosis and reporting in many countries. However, rabies is a vaccine-preventable disease as timely pre-exposure vaccination and post-exposure prophylaxis (PEP) are 100% effective at preventing deaths.

PEP consists of a series of rabies vaccine and in some cases, rabies immunoglobulin (RIG) injections administrated after suspected exposure to rabies. In Laos, very few data are available about the real burden of rabies at the human and veterinary level. Therefore, based on the previous experiences of Dr Cécile Troupin in the Pasteur Network at Paris, Guinea and Cambodia, a new theme on rabies will be developed in 2023 at IPL.

Overview of rabies situation in Laos

To our knowledge, only few data on the rabies situation in Laos are currently available. Thus, an overview of the current situation of rabies in Laos seems mandatory to determine the future activities at IPL. As rabies is a zoonotic disease, this overview needs to be performed at human and veterinary health levels. A pilot study will be performed in Vientiane capital and in 2 or 3 provinces (to be selected) in order to (i) understand how the reporting of data related to rabies cases is organized and (ii) collect the data that are available.

Even if it is difficult to know in advance which data we will have access to, at human health level, it will be interesting to determine: i) the number of medical centres which perform PEP after bites; ii) which PEP protocols are used in Laos (with or without immunoglobulins); iii) the number of dog bites in humans and among them the number of persons receiving a full PEP regimen and iv) the number of rabies human cases.

At veterinary level, in collaboration with the National Animal Health Laboratory (NAHL), we will try to collect information on: i) the number of dog bites in humans, dogs or cattle; ii) the number of dogs put in observation after bites; iii) the number of dog samples submitted for biological diagnosis at the NHAL; iv) the number of dog rabies cases and v) the number of vaccinated dogs.

Implementation of rabies diagnosis tools for human suspected cases

In developing countries, the real burden of rabies still remains unknown. This is due to the difficulty to obtain, in the local settings, a diagnostic confirmation for each suspected case, which exclusively relies on laboratory analysis.

The confirmation of rabies human cases relies exclusively on laboratory analysis, with the gold standard technique being the detection of viral antigens in brain biopsies. However, this technique is only possible at the postmortem stage and it is rarely achievable in local settings, due to the difficulty to have access to this invasive tissue. Alternative samples and techniques have been developed for the ante-mortem diagnosis of human rabies, with the detection of viral nucleic acids in serial saliva samples and/or in skin biopsy by RT-PCR (real-time or conventional).

Thus, the Medical Virology and Rabies group will set-up the molecular tools at IPL to detect rabies in saliva and/ or skin biopsy samples at ante-mortem stage. Awareness of medical teams on the need of perform biological rabies diagnosis will be mandatory to be able to have access to suspected cases. The group will rely on the hospital network developed since 2010 in Vientiane Capital and in some provinces for arbovirus or/and COVID-19 surveillance to start to collect rabies suspected samples.

Sequencing of rabies positele sample

To date, no positive rabies samples are available at IPL and therefore we will start a collaborative project with the NHAL, in order to sequence rabies positive samples from dogs, that have been submitted for diagnosis. A retrospective analysis of strains from the last 10 years will allow us to understand the dynamics of rabies circulation in dogs and potentially identify introductions from neighboring countries. Moreover, in the future, a percentage of positive samples detected by NHAL (to be determined) will be sent to IPL for genetic characterization.

The sequencing of rabies strains will be performed either by Sanger sequencing (nucleoprotein or/and glycoprotein gene) or by NGS sequencing that will be implemented in the lab in 2023 for COVID-19 and arbovirus surveillance.