Rabies: Still a silent killer targeting the poor

Rabies mortality and morbidity associated with animal bites in Africa: a case for integrated rabies disease surveillance, prevention and control: a scoping review

OBJECTIVE

The objective of this scoping review was to map the current situation and available evidence and gaps on rabies morbidity, mortality, integrated rabies surveillance programmes, and existing prevention and control strategies in Africa.

METHODS

We conducted a systematic scoping review following the Joanna Briggs methodology and Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews checklist. Medline, Embase, CINAHL (EBSCOHost), Scopus, Web of Science and rabies web conferences were used to search for peer-reviewed publications between January 1946 and May 2020. Two researchers reviewed the studies and extracted data based on author (year) and region, study design and data collection duration, participants/comparators, interventions, control conditions/exposures and outcomes (rabies mortality and morbidity) and key findings/gaps/challenges. The results were reported narratively using Arksey and O'Malley's methodological framework.

RESULTS

Electronic search yielded 2775 records, of which 43 studies were included. A total of 543 714 bite victims were censored through the included studies. Most of the victims were less than 15 years of age. The studies included rabies morbidity (21) and mortality (15) fluctuating in space and time across Africa depending on countries' rabies prevention and control practices (16). Others were surveillance (nine studies); surveillance and prevention (five studies); management and control (seven studies); and surveillance, prevention and control (six studies). We found challenges in rabies reporting, existing dog vaccination programmes and post-exposure prophylaxis availability or compliance.

CONCLUSION

This study found challenges for dog rabies control and elimination in Africa and the need for a policy to drive the goal of zero dog-transmitted rabies to humans by 2030.This is an open-access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build on this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated and the use is non-commercial (see http://creativecommons.org/licenses/by-nc/4.0/).

Laser-assisted skin delivery of immunocontraceptive rabies nanoparticulate vaccine in poloxamer gel

A painless skin delivery of vaccine for disease prevention is of great advantage in improving compliance in patients. To test this idea as a proof of concept, we utilized a pDNA vaccine construct, pDNAg333-2GnRH that has a dual function of controlling rabies and inducing immunocontraception in animals. The pDNA was administered to mice in a nanoparticulate form delivered through the skin using the P.L.E.A.S.E.® (Precise Laser Epidermal System) microporation laser device. Laser application was well tolerated, and mild skin reaction was healed completely in 8 days. We demonstrated that adjuvanted nanoparticulate pDNA vaccine significantly upregulated the expression of co-stimulatory molecules in dendritic cells. After topical administration of the adjuvanted nano-vaccine in mice, the high avidity serum for GnRH antibodies were induced and maintained up to 9 weeks. The induced immune response was of a mixed Th1/Th2 profile as measured by IgG subclasses (IgG2a and IgG1) and cytokine levels (IFN-γ and IL-4). Using flow cytometry, we revealed an increase of CD8+ T-cells and CD45R B cells upon the administration of the adjuvanted vaccine. Our previous study used the same pDNA nanoparticulate vaccine through an IM route, and a comparable immune response was induced using P.L.E.A.S.E. However, the vaccine dose in the current study was four-fold less than what was applied through the IM route.We concluded that laser-assisted skin vaccination has a potential of becoming a safe and reliable vaccination tool for rabies vaccination in animals or even in humans for pre- or post-exposure prophylaxis.

A dog bite study in a dog rabies-affected area in South Africa

Background

Rabies is an untreatable and highly fatal viral zoonosis. Despite the ability to control and prevent the disease, it is estimated that one person dies of rabies every 10 minutes in developing countries. However, the true burden of the disease remains undefined in most developing countries because of a lack of systematic surveillance. Dog bite data obtained from healthcare facilities where dog bite victims seek medical care may provide an additional source of information that can be used to inform the burden of disease and identify points for interventions for improved delivery of post-exposure prophylaxis (PEP) to prevent the disease.

Methods

A descriptive epidemiological study was conducted using data obtained from dog bite registers and patient case files at a healthcare facility for a two year period (2015-2017).

Results

The study reported frequency, demographics, source, geographic and temporal distribution of bite cases reported to a hospital serving a rabies-affected community. In addition, the post-exposure management of dog bite cases at this facility is described.

Conclusion

Dog bites was not an infrequently reported at the healthcare facility, with up to 29 cases reported in a month during the study period. The affected population was defined and it is motivated that this information is useful for targeted health interventions. Findings related to the delivery of PEP may also be used to direct training and re-training of healthcare workers for improved delivery of PEP.

Descriptive assessment of rabies post-exposure prophylaxis procurement, distribution, monitoring, and reporting in four Asian countries: Bangladesh, Bhutan, Cambodia, and Sri Lanka, 2017-2018

BACKGROUND

There are approximately 35,000 human deaths from rabies in Asia annually. Rabies can be prevented through timely post-exposure prophylaxis (PEP) consisting of wound washing, rabies vaccine, and in some cases, rabies immunoglobulin (RIG). However, access to rabies PEP often remains limited to urban areas and is cost-prohibitive. There is little information on procurement, distribution, monitoring, and reporting of rabies PEP.

METHODS

We interviewed key informants in the public sector from various levels in Bangladesh, Bhutan, Cambodia, and Sri Lanka between March 2017 and May 2018 using a descriptive assessment tool to obtain information on procurement, distribution, monitoring, and reporting of rabies PEP. These four countries in Asia were chosen to showcase a range of rabies PEP systems. National rabies focal points were interviewed in each country and focal points helped identify additional key informants at lower levels.

RESULTS

A total of 22 key informants were interviewed at various levels (central level to health facility level) including national rabies focal points in each country. Each country has a unique system for managing rabies PEP procurement, distribution, monitoring, and reporting. There are varying levels of PEP access for those with potential rabies exposures. Rabies PEP is available in select health facilities throughout the country in Bangladesh, Bhutan, and Sri Lanka. In Cambodia, rabies PEP is limited to two urban centers. The availability of RIG in all four countries is limited. In these four countries, most aspects of the rabies PEP distribution system operate independently of systems for other vaccines. However, in Bhutan, rabies PEP and Expanded Programme on Immunization (EPI) vaccines share cold chain space in some locations at the lowest level. All countries have a monitoring system in place, but there is limited reporting of data, particularly to the central level.

CONCLUSION

Systems to procure, deliver, monitor, and report on rabies PEP are variable across countries. Sharing information on practices more widely among countries can help programs to increase access to this life-saving treatment.

Overview of rabies post-exposure prophylaxis access, procurement and distribution in selected countries in Asia and Africa, 2017-2018

BACKGROUND

Rabies is a neglected zoonotic disease with a global burden of approximately 59,000 human deaths a year. Once clinical symptoms appear, rabies is almost invariably fatal; however, with timely and appropriate post-exposure prophylaxis (PEP) consisting of wound washing, vaccine, and in some cases rabies immunoglobulin (RIG), the disease is almost entirely preventable. Access to PEP is limited in many countries, and when available, is often very expensive.

METHODS

We distributed a standardized assessment tool electronically to a convenience sample of 25 low- and middle-income countries in Asia and Africa to collect information on rabies PEP procurement, forecasting, distribution, monitoring and reporting. Information was collected from national rabies focal points, focal points at the World Health Organization (WHO) country offices, and others involved in procurement, logistics and distribution of PEP. Because RIG was limited in availability or unavailable in many countries, the assessment focused on vaccine. Data were collected between January 2017 and May 2018.

RESULTS

We received responses from key informants in 23 countries: 11 countries in Asia and 12 countries in Africa. In 9 of 23 (39%) countries, rabies vaccine was provided for free in the public sector and was consistently available. In 10 (43%) countries, all or some patients were required to pay for the vaccine in the public sector, with the cost of a single dose ranging from US$ 6.60 to US$ 20/dose. The primary reason for the high cost of the vaccine for patients was a lack of funding at the central level to subsidize vaccine costs. In the remaining 4 (17%) countries, vaccine was provided for free but was often unavailable so patients were required to purchase it instead. The majority of countries used the intramuscular route for vaccine administration and only 5 countries exclusively used the dose-sparing intradermal (ID) route. Half (11/22; 50%) of all countries assessed had a standardized distribution system for PEP, separate from the systems used for routine childhood vaccines, and almost half used separate storage facilities at both central and health facility levels. Approximately half (9/22; 41%) of all countries assessed reported having regular weekly, monthly or quarterly reporting on rabies vaccination.

CONCLUSIONS

While all countries in our assessment had rabies vaccines available in the public sector to some extent, barriers to access include the high cost of the vaccine to the government as well as to patients. Countries should be encouraged to use ID administration as this would provide access to rabies vaccine for many more people with the same number of vaccine vials. In addition, standardized monitoring and reporting of vaccine utilization should be encouraged, in order to improve data on PEP needs.

Rabies vaccine and immunoglobulin supply and logistics: Challenges and opportunities for rabies elimination in Kenya

Prompt provision of post-exposure-prophylaxis (PEP) including vaccines and rabies immunoglobulin (RIG) to persons bitten by suspect rabid dogs is a key strategy to eliminating human deaths from dog-mediated rabies in Kenya by 2030. We assessed the availability, forecasting and supply chain logistics for rabies PEP in Kenya, compared with the system used for vaccines in the expanded program of immunization (routine vaccines). Semi-structured questionnaires capturing data on forecasting, procurement, distribution, cold chain and storage, monitoring and reporting for routine vaccines and rabies vaccines and RIG were administered to 35 key personnel at the national, county, sub-county and health facility levels in five counties. Results showed large variability in PEP availability (stockouts ranged from 3 to 36 weeks per year) with counties implementing rabies elimination activities having shorter stockouts. PEP is administered intramuscularly using the 5-dose Essen regimen (day 0, 3, 7, 14 and 28). PEP costs to bite patients were reported to range from 10 to 15 US dollars per dose; RIG was seldom available. A less robust supply and logistics infrastructure is used for rabies PEP compared to routine vaccines. Forecasting and monitoring mechanisms for rabies PEP was poor in the study counties. The supply of vaccines from the national to the sub-national level is mainly through two government agencies and a private agency. Since government decentralization, the National Vaccine and Immunization Program has remained as the main supplier of the routine vaccines, playing a lesser role in the supply of rabies bio-logicals. Adoption of the dose-saving intradermal route for PEP administration, reduction of PEP costs to patients, and placing rabies vaccines within the routine vaccines supply and logistics system would significantly improve PEP availability and accessibility to persons at risk of rabies; a critical step to achieving elimination of human deaths from rabies.

Evaluation of an adjuvanted hydrogel-based pDNA nanoparticulate vaccine for rabies prevention and immunocontraception

Immunocontraceptive vaccination is becoming an acceptable strategy in managing animal populations. Mass vaccination of dogs is the most cost-effective and efficient method to control rabies, and combination of rabies vaccination and animal population control will be an added advantage. In this study, we developed an adjuvanted hydrogel-based pDNA nanoparticulate vaccine for rabies protection and immunocontraception. In vivo, we observed an immune response skewed toward a Th2 type, in contrast to the Th1 type in our previous pDNA study. The observation was verified by the IgG2a/IgG1 ratio (<1), and cytokine expression profile of IL-4 and IFN-γ. The humoral immune response is key for rabies protection and a GnRH antibody-based immunocontraception. In mice, anti-GnRH antibody titers were detected 4 weeks after immunization and lasted for 12 weeks, post animal experiment was terminated. The adjuvanted pDNA nanoparticulate vaccine shows promise for future studies evaluating protection from rabies challenge and prevention of animal breeding.