Rabies in a postpandemic world:resilient reservoirs,redoubtable riposte,recurrent roadblocks,and resolute recidivism

Rabies is an ancient disease.Two centuries since Pasteur,fundamental progress occurred in virology,vaccinology,and diagnostics—and an understanding of pathobiology and epizootiology of rabies in testament to One Health—before common terminological coinage.Prevention,control,selective elimination,and even the unthinkable—occasional treatment—of this zoonosis dawned by the twenty-first century.However,in contrast to smallpox and rinderpest,eradication is a wishful misnomer applied to rabies,particularly post-COVID-19 pandemic.Reasons are minion.Polyhostality encompasses bats and mesocarnivores,but other mammals represent a diverse spectrum of potential hosts.While rabies virus is the classical member of the genus,other species of lyssaviruses also cause the disease.Some reservoirs remain cryptic.Although global,this viral encephalitis is untreatable and often ignored.As with other neglected diseases,laboratory-based surveillance falls short of the notifiable ideal,especially in lower-and middleincome countries.Calculation of actual burden defaults to a flux within broad health economic models.Competing priorities,lack of defined,long-term international donors,and shrinking local champions challenge human prophylaxis and mass dog vaccination toward targets of 2030 for even canine rabies impacts.For prevention,all licensed vaccines are delivered to the individual,whether parenteral or oral–essentially‘one and done’.Exploiting mammalian social behaviors,future‘spreadable vaccines’might increase the proportion of immunized hosts per unit effort.However,the release of replication-competent,genetically modified organisms selectively engineered to spread intentionally throughout a population raises significant biological,ethical,and regulatory issues in need of broader,transdisciplinary discourse.How this rather curious idea will evolve toward actual unconventional prevention,control,or elimination in the near term remains debatable.In the interim,more precise terminology and realistic expectations serve as the norm for diverse,collective constituents to maintain progress in the field.

Molecular Characterization of China Human Rabies Vaccine Strains

To understand the molecular characteristics of China human rabies vaccine strains, we report the full-length genome of the aG strain and present a comprehensive analysis of this strain and almost all available lyssavirus genomes （58 strains） from GenBank （as of Jan 6, 2011）. It is generally considered that the G protein plays a predominant role in determining the pathogenicity of the virus, to this end we predicted the tertiary structure of the G protein of aG strain, CTN 181 strain and wild type strain HN 10 based on the crystal structure of Vesicular stomatitis virus （VSV） G. The predicted RABV G structure has a similar topology to VSV G and the ectodomain can be divided into 4 distinct domains DI - DIV. By mapping the characterized mutations to this structure between China vaccine strains and their close street strains, we speculate that the G303（P-H） mutations of CTN181 and HN10 causing D II 3D change may be associated with the attenuated virulence in both strains. Specifically, the two signature mutations （G165P and G231P） in the aG strain are withinβsheets, suggesting that both sites are of structural importance.

Pilot-Scale Production of Lyophilized Inactivated Rabies Vaccine Candidate in Vero Cells under Fully Animal Component-Free Conditions Using Microcarrier Technology and Laboratory Animal Trials

The upstream process was carried out in an animal component-free medium on Cytodex 1 microcarriers. Recombinant trypsin is a non-animal derived protease used as an alternative to animal-derived trypsin. To inactivate recombinant trypsin, a soybean trypsin inhibitor (STI) should be added to the medium. A protocol was first tested in T-flasks and then passaged to 500 mL and 3 L spinner flasks. Cell detachment was completed in 10 - 12 min, and 0.4 g/L STI was added to a 3L spinner, and cells were transferred into a 30 L stirred tank bioreactor. On day 5, the cell density had reached its maximum (around 1.8 × 106 cells/mL). At an MOI of 0.3 with serum-free medium conditions, cell infection yielded a maximal rabies virus titer of 1.82 × 107 FFU/mL at 5 days. All cell culture conditions and virus growth kinetics in serum-free media were investigated. In conclusion, Vero cells were grown on Cytodex 1 with serum-free media and a high amount of rabies virus was obtained. A mouse challenge was used to determine the immune response to an inactivated rabies virus vaccine candidate. Also, we evaluated inactive rabies vaccine candidate safety, and immunogenicity in mice, sheep, horses, and cattle. We found that no horses, sheep, or cattle who were given vaccine IM at 3.2 IU/dose exhibited any clinical sign of disease and all developed high VNA titers (up to 10.03 IU/mL) by 3 - 4 WPI. After the accelerated stability studies, the lyophilized inactivated rabies vaccine candidate showed enough antigenic potency (2.6 IU/mL) in the mouse challenge test. Also, 18-month long-term stability studies showed enough immune response (1.93 IU/mL) on day 14. The activity of the vaccine candidate showed a good immune response and safety criteria that meet WHO requirements. This is the first pilot-scale mammalian cell-based viral rabies vaccine production study in Türkiye that used microcarriers.

中国狂犬病病毒基因分型及分布研究进展

Lyssavirus广泛存在于全球各地,种类较多。作为其中一员,狂犬病病毒造成的危害最为严重,其致病性极强。近年来,中国狂犬病的防治工作取得一定成效,然而,由于地域广阔、人口众多且分布密集,狂犬病的防控仍然面临一定的困难。为了制定有针对性的防控措施,推进中国狂犬病研究,了解该病的分子流行病学特征至关重要。本文综述了世界及我国最新的Lyssavirus分类研究,探讨我国狂犬病病毒在犬和野生动物间的种群类型、传播宿主以及流行情况。

Progress towards dog-mediated rabies elimination in PR China:a scoping review

Background Rabies continues to be a serious threat to global public health endangering people’s health and public health safety.In the People’s Republic of China,multi-sectoral and comprehensive prevention and control strategies have aimed to extensively curb human rabies transmission.Here,we examine the current state of rabies infection in China,explore strategic interventions put in place in response to WHO’s ambition of“Zero rabies deaths by 2030”and critically assess the constraints and feasibility of dog-mediated rabies elimination in China.Methods This study analyzed and evaluated the process towards dog-mediated rabies elimination in China from five perspectives:namely,human,dog,policy,challenge,and prospects.Evidence-based data on progress of dog-mediated rabies elimination in China was derived from a number of sources;a literature search was undertaken using PubMed,Web of Science and CNKI databases,distribution data for human rabies cases as derived from the Data-center of the China Public Health Science and policy and document data were obtained from official websites of the relevant China ministries and commissions.Results The incidence of human rabies cases in China have shown a downward trend year-on-year since 2007.Implementation of a government-led,multi-sectoral“One Health”approach to combating rabies has driven down the total number of rabies deaths nationwide to around 200 in 2020.The number of provincial-level administrative divisions(PLADs)reporting human cases of rabies has also decreased to 21 in 2020,13 of which reported less than 10 cases.Furthermore,the number of outpatient visits seeking rabies post-exposure prophylaxis has risen dramatically over the past two decades,with demand being 15 times higher than it was initially.There remain however,significant gaps in rabies elimination outcomes across the different regions of China.To date the target of achieving a canine rabies vaccination rate of>75%has not been met.The challenges of rabies immunization of dogs and dog management in underdeveloped cities and rural areas need to be addressed together with more effective animal surveillance and rabies risk from and too wildlife and livestock.Conclusions The Chinese government-led,multi-sectoral“One Health”approach to combating rabies and has made significant progress over the past decade.Development and adoption of more cost-effective One Health strategies can achieve more nationally beneficial rabies elimination outcomes.The ambitious target of“Zero rabies deaths by 2030”can be met through establishment of long-lasting herd immunity in dogs by means of dog mass vaccination campaigns,dog population management,epidemiological surveillance and the application of large-scale oral rabies vaccine to eliminate rabies in wild animals coupled with deployment of cost-effective human post-exposure prophylaxis,and community education.

Human rabies encephalomyelitis in the background of rabies outbreak in animals in Gelephu,Bhutan,2023:a case report

Background Rabies continues to pose significant public health challenges in many developing countries including Bhutan.A probable case of rabies was admitted to our hospital and its reporting led to the uncovering of an outbreak in domestic and wild animals.We discuss the challenges in the diagnosis and management of rabies in a resource-limited setting.Case presentation A 35-year-old male presented with intermittent fever,bilateral lower limb weakness that was rapidly progressive,urinary incontinence with episodes of palpitations and sweating.He had sustained a Category III bite on the right lower thigh with four bite marks,inflicted by a stray dog.He had received post-exposure prophylaxis with intra-dermal anti-rabies vaccine.On initial examination,the patient was in distress but cooperative for the interview.He had pulse rate ranging from 60 to 100/min with episodes of diaphoresis and palpitations,but with normal capillary blood glucose.In the lower limb,the muscle power was zero with absent tendon reflexes in the lower limb and impaired abdominal reflex below T10 level.He had hyperaesthesia below T8,hydrophobia,aerophobia and photophobia.He had multiple spontaneous fasciculations in both the thighs and right deltoid and these later involved the intercostal muscles,neck and face muscles.He had altered sensorium and desaturation for which he required mechanical ventilation.Polymerase chain reaction for rabies virus was negative in cerebrospinal fluid and saliva.Rabies virus neutralizing antibody was negative in cerebrospinal fluid but had high titres in the serum.He received Human Rabies Immunoglobulin after admission.He was managed in the intensive care unit and died 23 days later.After this case was notified,a rapid response team was deployed in the field,and uncovered rabies outbreak in animals in the locality.Conclusions This case called for a serious evaluation of the country’s efforts in achieving zero rabies deaths by 2030.The management of this case identified several critical areas of context-specific interventions in Bhutan.There is also an urgent need to improve diagnostic capabilities at the national reference laboratory and enhance the technical competencies of healthcare workers in the management of dog bite cases.