A Retrospective Disease Surveillance Based Approach in the Investigation and Linkage of Human Brucellosis to Animal Sources.

A Retrospective Disease Surveillance Based Approach in the Investigation and Linkage of Human Brucellosis to Animal Sources: One Health Approach Complementary Strategy Applicable in Nomadic Pastoralism, a Case Study of Turkana County, Kenya.

Abstract

The research provides an insight on a retrospective disease surveillance based approach that will be fundamental in the investigation and linkage of human brucellosis (zoonotic disease) to animal sources, domestic and wild animals.  The retrospective disease surveillance based approach complements One Health Approach. One Health Approach is a collaborative and transdisciplinary initiative working locally, nationally and globally to improve the health of humans, animals and the environment (Aguirre et al., 2016). Despite One Health Approach having a working framework, teething challenges are preventing the initiative from working effectively. A revamp of the approach with the provision of clear procedural designs, engagement of respective stakeholders with clearly stated roles, the establishment of a one-health network system with well-defined funding mechanisms and incorporation of the approach in the existing health infrastructure and systems are fundamentally required (Vesterinen et al., 2019). The retrospective disease surveillance based approach utilises the available health and animal husbandry system structures. The approach leverages on the outpatient diagnosis and laboratory testing services availed at the health facility setups and disease surveillance initiative programs such as Community Event-Based Surveillance (CeBS) being implemented at the community level.

Brucellosis is the most rampant zoonotic disease affecting the nomadic population in Kenya. The disease transmission made possible because of poor devastating levels of environmental sanitation and personal hygiene brought about by scarce or lack of adequate water as well as behavioural characteristics or habits that arise from the nomadic pastoralism settings. Being that consumption of unpasteurized milk, meat and contact with the animal is a cultural practice in most pastoral communities across Kenya. Identification of a suspected brucellosis case is established through diagnosis from a clinician or veterinarian for animals, a confirmation of a brucellosis case is done by conducting diagnostic laboratory serological and microbiological brucellosis tests, blood samples are cultured in a modified biphasic medium(Morales-Garcia et al., 2015).

The research paper gives insight on how the surveillance team working under the One Health Approach can retrospectively conduct disease surveillance by utilising the already established human health and animal husbandry infrastructure to investigate and link a confirmed brucellosis human case to a specific herd of animal source in a specified geographical location(with exact geo-coordinates). This will facilitate vaccination and treatment of the diseased herd thus preventing and mitigating the spread of the infection to humans and other herd whilst controlling the migration of the infectious disease through human, animal or the environment. Identification, treatment and vaccination of human and animals who encountered the herds and sanitising of the environment are some of the expected results.

Introduction

An effective coordination and efficient management of efforts across all sectors are fundamental in addressing critical global health issues such as infectious diseases outbreaks and antimicrobial resistance. One Health Approach is an integral effort of attaining optimal health for people, animal and the environment. Addressing complex health challenges require a well-designed, multistage and multi-sectoral support system. An increased risk of emerging, re-emerging diseases and health threats are driven by dynamic changes in the environment that destabilize the interfaces of human and animal health. Defined as the cohesive effort of multi-sectors working for the attainment of optimal health for the people, animal and the environment, One Health approach apply different collaborative models within and across countries to promote effectiveness and efficiency in managing health threats. Community-Based Surveillance and Community Event-Based Surveillance are disease and event surveillance models that complement the One Health Approach initiative. Multiple operational challenges have been a hindrance of universal defining, such as recognizing complex global health challenges for collaboration and action. Countries are always attending to competing challenges thus integrations and support of One Health Approach across the board becomes difficult. Various health, veterinary and environment professionals are involved in the implementation of the One Health Approach at the management and community level. Being that three different fields of study and area of operations are clamped into one, equitable funding is required for multi-sectoral engagement to prevent imbalanced participation among human, animal, environmental and ecosystem professionals (Vesterinen et al., 2019).

Brucellosis is a global zoonotic disease, one of the most widespread diseases in the world. Brucella arbutus, Brucella melitensis, and Brucella suis are Brucella species that cause the disease in humans and domestic animals. The mode of disease infection to humans is through consumption of raw milk, fermented milk produced from unpasteurized milk and by contact of infected animals or animal by-products such as meat and skins (Morales-Garcia et al., 2015). In the inception of WHO in 1948, brucellosis was a disease of public health importance, this is due to the physical suffering, reduced work output for those infected, as well as decrease livestock productivity(Mableson, Okello, Picozzi, & Welburn, 2014). Vaccination of livestock against brucellosis is beneficial to public health and three times more profitable from a health and community perspective (Zinsstag et al., 2018).

A retrospective approach involves tracing back disease transmission pathway using models, suitability of the intermediate host and factors contributing to the progression of the disease in human and animals whilst considering all other possible environmental and climatic factors supporting or promoting the thriving of the infection or disease. The retrospective approach simply means tracing back the steps from the confirmed disease or event (progression), the number of possible infections from laboratory investigations and the potential number of intermediary host that are significant in calculating the case fatality rate and developing the spread of infection models respectively.

Materials and Methodology

Being that the retrospective approach in the investigation and linkage of human brucellosis to animal sources is a new strategy and it has yet to be fully explored, methodology and insights on its implementation will be outlined and highlighted in this section.  

For the implementation of this approach efficiently and effectively; there will be collation and collection of secondary data from diagnosed and confirmed cases that attend the hospitals and laboratories for testing respectively. For efficiency of the process, a team of health professional is involved in various department or sections, at hospital and community setups.

Health Facility Setup.

Outpatient and Inpatient Department: Diagnosis of Brucellosis Disease

Medical Practitioners: Clinical Officer or Nurse is involved in the diagnosis of brucellosis disease as per the description. He or she captures the information of the patient, place of residence including major landmarks and name of kraal/community setup and village.

Laboratory Department: Confirmatory Tests: Serological and Microbiological Brucella tests

Brucellosis disease is confirmed through serological and microbiological Brucella test, a laboratory confirmatory test, done by a Medical Laboratory Technologist.

Results from the laboratory are sent to the outpatient or inpatient department to facilitate drug prescription to the patient.

Sources of Data in this section is the Diagnosis Register and Confirmatory, Laboratory Register.

Information of patients of the laboratory-confirmed brucellosis cases is collected by the Clinical Officer and it’s cascaded to the Community Health Assistant (Community Level): Confidentiality of the adhered to during this process.

Community Level

At the community level, community health strategy and surveillance systems that exist such as Community Health Volunteers and Community Event-Based Surveillance respectively will be tasked with tracing the specific village the brucellosis cases resonated from. The Community Health Assistant shares the information and task the Community Mobilisers, Community Health Volunteers, and Community Animal Disease Reporters to:

1)   Backtrack on the specific village the brucellosis case originated from,

2)   Identify and locate the herd of animals that produce milk or meat for consumption.

Geolocation of the village, the herd of animals, various water points and animal interaction points are captured via KoboCollect or Open Data Kit Applications.

Feedback of this information is relayed back to the Community Health Assistant who passes it to the Clinical Officer or Nurse whose health facility covers the village or population.

This information is communicated to the One Health task force that constitutes of the Epidemiologists, Veterinary and Environmentalist at SubCounty Level.

The task force undertakes a collaborated, coordinated and multisector response to tackle the situation: conduct a risk assessment and setting up of mitigation measures

1.    Assess the health status of the available animals in the area: this is through taking animal blood samples for laboratory analysis for Brucella, and conduct vaccination against the disease in the village and nearby villages: Task undertaken by Veterinary and Animal Health Assistance.

2.    Epidemiologist: Risk assessment of human transmission and conduct health promotion and sensitization on control mitigation and prevention strategies. Community Health Volunteers could also identify more human cases presenting with similar signs and symptoms.

3.    Environmentalist: Assessment of the possibilities of environmental factors that support transmission and inefficiency in control protocols and prevention measures despite deploying the mitigation measures.

Flow Diagram: A Retrospective Disease Surveillance Based Approach in the Investigation and Linkage of Human Brucellosis to Animal Sources

Expected Results

A coordinated network of specialists implementing retrospective disease surveillance approach in the investigation and linkage of zoonotic diseases at the community level. The approach does not necessarily apply to brucellosis only but to other similar zoonotic diseases such as anthrax, hydatidosis and rabies. This approach will geologically and specifically identified a Brucella diseased herd of animals thus facilitate prioritization when it comes to resource mobilization for vaccination and establishing environmental mitigation measures to support control of transmission of the infection to human or animal.

Besides, implementation of the strategy will ensure enhancement of sensitization of community and health promotion on prevention and treatment of brucellosis disease in areas where it is prone.

The implementation of retrospective disease surveillance based approach in the investigation and linkage of human brucellosis to the animal source will complement the One Health Approach. This will establish and provide a One Health complementary network, which can be used in the retrospective investigation and linkage of any zoonotic disease to establish source, and together with the available human resource on the network, holistically design and implement prevention, control and treatment of the cases respectively.

Public Health Implications of the Strategy

Treatment of brucellosis disease in domestic animals by use of antibiotics has been determined to be unsuccessful; this is due to the intracellular survival and adaptability in the macrophages of Brucella (Khurana et al., 2021). Brucellosis is a disease of public health importance since it has an economic impact both on human and animal health. Infertility in both sexes and late-term abortions are some of the economic losses experience and brought about by brucellosis disease in animals. According to World Health Organization, brucellosis is one of the neglected zoonotic disease occurring in highly poverty-stricken developing countries. Vaccination of the herd with the specified host species is the most efficient strategy for the elimination and eradication of brucellosis disease. (Dadar, Tiwari, Sharun, & Dhama, 2021).

The retrospective disease surveillance based approach complements one health approach. One Health is an integral approach to control the transmission of zoonotic diseases in endemic areas. Implementation of the strategy will establish a mechanism of tracing zoonotic disease to the specific source; livestock or herd of animals thus ensure easy quarantine, control and prevention of further transmission of the disease.

Hospital Setup: Brucellosis cases diagnosed and confirmed at hospital setups will trigger a passive response at the community level, which will be fundamental in the control of further transmission of the zoonotic disease. Data collected at the health facility level is used to retrospectively trace the spread, transmission, and occurrence of the disease. The Clinical Officer, Nurse and Medical Laboratory Technologist are integral at this level.

Community Level: The information collected of the brucellosis cases will be used to geographically analyses the occurrence of the disease at the community level; trace the herd of the suspected diseased animals while considering interaction with other herds of animals and humans as well as environmental factors influencing transmission. Use of applications such as KoboCollect and Open Data Kit to capture geo-codes (longitudes’ and latitudes) of the geographical location of the suspected diseased animals, water points, possible points of interactions will be shared to facilitate the development of patterns and trends at the county level. Communication of community-based events of animals experiencing sign and symptoms of brucellosis disease infection will be made to the nearest health facility as well as the County level.

County or SubCounty Level: After receiving a report from the Community through Community Health Assistant, which is verified by the facility in charge of the nearest health facility. The Epidemiologist (SCDSC), the SubCounty Veterinary officer and the Environmentalist implement a coordinated and multidisciplinary response in the affected area to conduct a risk assessment of the degree and the possibility of further transmission of the disease respectively. Blood samples for animals will be collected for laboratory confirmatory tests and gene-expert to determine the type of Brucella the herd of animals has been infected with, which will be fundamental in the prescription of treatment, whenever possible. The suitable effective and efficient mitigation measures for the control and prevention of the transmission of human-animal and ecosystem zoonotic disease is collectively reached by the multidisciplinary team and implemented concurrently.

Data collected using the questionnaire on KoboCollect or ODK is analysed and utilized in the coordination of geographical environmental mitigation measures. The information will also be used to prioritise vaccination in areas with the herd of animals that are gravely affected by the zoonotic disease and pin-point areas of possible human-animal interaction where there is a high transmission of the disease hence provide a corrective measure. The information will geo-link animal cases with human cases, which will assist in prioritizing areas for conducting mass treatment of humans and sensitize the community through behaviour change communication, including health promotion.

Limitations

The aim of the retrospective disease surveillance based approach is to 

compliment One Health, therefore most of the limitations fall under the system it is meant to strengthen:

1.    Funding: funding for One Health initiatives have been a challenge. One Health Approach incorporates several specialists, departments and ministries.

2.    Laboratory Services: The serological and microbiological diagnostic test for Brucella is only available in well-equipped laboratories, this means there will be challenges in the coordination and sample transportation to other areas with the available service: might not be available at County Government Level.

3.    One Health Approach is still ineffective and inefficient: The existing systems working independently, not cohesively. The approach is not fully operational, it is still a challenge: coordinating a multidisciplinary team working in three ministries that have different priorities.

4.    Human Resource: There is a lack of adequate human resource depending on the respective ministries. Human resource in the respective departments in the ministries and/or available stakeholders is also inadequate

5.    Coordination and Cooperation: Integration of initiatives or mitigation activities not well coordinated or synchronized. This has been earlier highlighted, this is because of different governance of respective departments or ministries with competing activities are different areas prioritized for funding.

6.    More Research is needed: Further research, review and revamp on One Health Approach is required.

Recommendations for the Limitations

1. The complete devolvement of health services at County Levels: there is a need of establishing relevant skillset through training and frequent capacity building of specialist and machine operators; the relevant equipment and health machinery to be made available by the National Government.
2. Human resource be made adequate; retraining of the staff could be significant in the successful implementation of the service
3. Funds need to be available to ensure implementation of One Health is effective and efficient
4. The Counties should select a One Health Approach Committee that will be also cascaded to SubCounty Level: the committee should be tasked with coordinating One Health initiatives and implementation plans which may be proposed by the SubCounty level
5. Counties should upscale the Laboratory Services, activation and equipping of various laboratories in SubCounty Hospitals should be prioritised.

Acknowledgements

I acknowledge my work colleagues: Dr Kevin Lomuria, Mr Gabriel Ekwom, Mr Robert Rotich, Mr Joshua Rutto, and Mr John Njuguna for their contributions on the research concepts that led to the successful completion and publishing of the research paper.

References

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Index

A flow diagram reviewing Bovine Brucellosis (Khurana et al., 2021)