Assessment of rodent-borne and zoonotic disease pathogens in humans, gogs and rodents and community awareness in Ngorongoro District, Tanzania
Loading...
Date
2024-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Sokoine University of Agriculture
Abstract
Bacteria and viruses carried by rodents, and domestic dogs can
have significant public health implications. Rodents are known
reservoirs of several zoonotic diseases, such as Hantavirus
hemorrhagic fever, Lassa fever virus, plague, tuberculosis and
leptospirosis. Also, domestic dogs carry zoonoses like rabies,
leptospirosis, salmonellosis, ehrlichiosis and borreliosis. Zoonotic
diseases pose a substantial risk to communities‘ health, mostly in
wildlife, domestic animals and human interface areas. Ngorongoro
district is the home of various wildlife and domestic animals
cohabiting with humans. The district is experiencing the expansion
of human activities which brings rodents into close proximity with
human settlements. Previous studies conducted in livestock and
human patients attending the health facilities have documented the
existence of antibodies of zoonoses like Rift Valley fever,
Brucellosis, Anthrax, and molecular detection of Bovine tuberculosis.
While previous studies have examined the transmission of
pathogens in livestock and hospital-based research in humans
within the district, the specific role played by rodents and domestic
dogs in transmitting pathogens remains largely unknown. This
research gap necessitated conducting a comprehensive
metagenomics study to assess the diversity and abundance of
bacteria and viruses circulating among rodents, domestic dogs and
humans as well as the communities understanding of rodent-borne
diseases, including RVF, in the Ngorongoro district of Tanzania. The
Rift Valley fever was frequently previously reported to occur within
livestock and human populations of the Ngorongoro district. The
disease caused significant morbidity and mortality in both livestock
including humans.
To address the objectives, the study used Illumina and Oxford
Nanopore technologies to identify bacteria and viruses in 530 blood
samples collected from 200 humans, 230 rodents, and 100 domestic
dogs. Numerous bacteria and viruses were detected and identified by using MiSeq and MinION sequencers with a Kraken2 data
analysis program. Moreover, the study used 3 focus groups, 20 key
informant interviews, and the questionnaire (N=352) to collect
information on communities‘ awareness on rodent-borne diseases
and Rift Valley fever. The logistic regression model was used to
examine the relationship between demographic factors and
communities‘ knowledge, attitudes and practices toward rodent-
borne diseases and RVF occurrences.
In all three hosts, various pathogenic and zoonotic bacterial species
were detected. Zoonotic airborne and contagious bacteria such as
Mycobacterium spp, Mycoplasma spp, Bordetella spp and
Legionella spp were spotted in rodents, domestic dogs and humans.
Arthropod-borne zoonotic bacteria like Bartonella spp, Borrelia spp,
and Rickettsia spp were detected in all three hosts, while Orientia
spp were found in rodents and dogs. Yersinia pestis, Streptobacillus
spp and Anaplasma spp were identified in rodents only. Waterborne
and foodborne zoonotic bacteria were also spotted in all three hosts,
including Leptospira spp, Brucella spp, Bacillus spp, and
Salmonella. Generally, rodents carried a high proportion of zoonotic
bacteria compared to dogs and humans. The detection of zoonotic
bacteria in all three hosts showed the possibilities of cross-species
transmission of infections between animals and humans sharing the
same environment.
Several viral families and species were detected and identified in
this study. A total of 20 RNA and 20 DNA viral families and
unclassified RNA viruses were detected. The majority of viral
families were detected in rodents when compared to domestic dogs
and humans. Peribunyaviridae, Hantaviridae, Phenuiviridae,
Flaviviridae, Coronaviridae, Orthomyxoviridae, Paramyxoviridae,
Retroviridae, Picornaviridae, Arenaviridae, Togaviridae, and
Tobaniviridae are zoonotic RNA viruses identified in rodents. The
zoonotic DNA viruses detected in rodents were Adenoviridae,
Poxviridae, Herpesviridae, Anelloviridae, and Circoviridae.
Peribunyaviridae and Hantaviridae viruses were identified in both rodents and humans, whereas Retroviridae was detected in rodents
and domestic dogs. Unclassified +ssRNA viruses were spotted in
domestic dogs and humans. Lastly, Herpesviridae was found in all
three hosts. In comparison with domestic dogs and humans, rodents
harboured potential zoonotic viruses of public health safety.
Result showed that 8.52% of respondents had good knowledge,
35.5% had a positive attitude, and 94.3% had good practices toward
rodent-borne diseases. The study revealed that only 28.13% of
participants were aware of rodent-borne zoonoses. The majority of
them (77.27%) believe that rodents are pests that destroy crops and
do not transmit pathogens. Moreover, the findings showed that the
majority of respondents (82.9%) live in huts which can provide
shelter for rodents. Additionally, except for education, the level of
knowledge had no significant relationship with most of the
participants‘ demographic variables. Respondents with secondary
education (p=0.017) had good knowledge of rodent-borne diseases
and management when compared to those without education.
Despite showing good practices, the communities still don‘t have
enough knowledge of rodent-borne infections.
The findings further showed that only 36.1%, 38.64%, and 16.19%
of participants had good knowledge, positive attitudes and effective
preventive practices about RVF occurrences, respectively. The
significant demographic variables related to good knowledge and
positive attitudes were gender (P<0.05), occupation (P<0.05) and
education (P<0.05). Male respondents had good knowledge of RVF
epidemiology. Individuals with formal education had good knowledge
and exhibited positive attitudes towards RVF occurrences.
Agropastoral members had a significantly negative attitude toward
RVF occurrences compared to pastorals (P=0.048). The study
revealed that the majority of respondents had poor knowledge,
negative attitudes and ineffective preventive practices towards RVF
epidemiology. Probably, these results were attributed to the lack of
regular education campaigns to increase community awareness of
the disease. This study novelty is based on the fact that it is the first to provide
the baseline information on the diversity of pathogenic and zoonotic
bacteria and viruses in rodents, domestic dogs and humans sharing
the same environment. Likewise, it established the levels of the
communities‘ knowledge, attitudes and practices toward rodent-
borne diseases including Rift Valley fever in Ngorongoro district for
the first time. The study population had inadequate knowledge and
negative attitudes toward rodent-borne diseases and RVF.
Therefore, one health multidisciplinary approach is recommended in
order to safeguard public and animal health from acquiring
zoonoses. Provision of health education should be a long-term
practice to prevent diseases outbreaks in Ngorongoro district and in
Tanzania at large.
Description
PhD Thesis
Keywords
bacteria, viruses, rodents, domestic dogs, humans, Knowledge, Attitudes, Practice, zoonoses, Ngorongoro, Tanzania., Metagenomics, Next-generation sequencing