Research Activity of HUCZCZ


▼ Surveillance of viral zoonoses in sub-Saharan Africa

Background    
    Recently, emerging and reemerging infectious diseases, such as SARS, Nipah, Hanta, Hendra, Influenza, Arena and Ebola virus infections, are appearing worldwide, and becoming of major concern to public health. All of these diseases are zoonoses whose causative agents infect both humans and animals. The agents are originally harmless in their natural host wild animals and occasionally transmit to other animal species including humans, causing infectious diseases. Since these zoonotic infections are not eradicable, it can be controlled only by taking preemptive measures to predict and prevent their outbreaks. This project includes surveillance of viral zoonotic agents in wild and domestic animals in sub-Saharan Africa, aiming to identify natural host animals carrying potential pathogens and to elucidate the transmission routes and factors involved in the spread and host range of viruses.

Activity
   We perform epidemiological research of pathogens, including Filoviruses etc., in Fruit bat in Zambia using RT-PCR, Eliza, and other methods. We also perform epidemiological research of pathogens, including Arenaviruses, Hantaviruses, Polyomaviruses in rodents in Zambia using RT-PCR, PCR, and Elisa methods. We have identified novel Arenavirus (designated as Luna virus) and Polyomavirus (designated as Mastomys Polyomavirus). Furthermore, we perform epidemiological research of pathogens, including Retroviruses, Filoviruses, Alphaviruses, Flaviviruses, and Polyomaviruses in Vervet monkeys and Chakma Baboon in Zambia using RT-PCR, PCR, Elisa, and other methods.

▼ Molecular epidemiology of protozoan and rickettsial diseases in Zambia

Background
    HAT is a tsetse-transmitted neglected tropical disease threatening over 60 million people in sub-saharan Africa (Fevre et al., 2005). HAT epidemics have been reported in Zambia’s neighboring countries (WHO, 2006). Although there are several unpublished HAT cases, there is paucity of published data on the current prevalence of HAT in Zambia, mainly because HAT is thought to claim fewer lives annually compared to malaria or tuberculosis. However, HAT could be under-reported but likely to be significant among remote rural Zambians in tsetse-infested Luangwa valley. Furthermore, most of the HAT cases could be misdiagnosed for malaria or other disseases due to similarities in presenting signs. Hence there is urgent need for HAT surveillance in Zambia. The main objective of our activity in Zambia is thus to determine the prevalence, routes of transmission and major reservoir hosts of HAT in Luangwa valley, Zambia.

Activity
   Trypanosomal parasites were detected in blood from a patient with a fever of unknown origin had been admitted to the hospital in Lusaka in January 2009. Parasites were isolated from the blood sample by inoculation into a mouse and identified as T. brucei rhodesiense based on the presence of serum resistance-associated antigen (SRA) gene. Therefore, we conducted surveillance of HAT in 2009 and 2010 in the Eastern Province of Zambia where the patient had been living. Several SRA-positive parasites were detected in samples of bovine blood and tsetse flies (Glossina palpalis). Furthermore, 3 strains were isolated from mice inoculated with salivary glands of tsetse flies, which were revealed to be SRA-positive. Genetic similarities among the isolate from the patient and those from tsetse flies were demonstrated by the microsatellite marker analysis. We are conducting surveillance of HAT in order to determine how wild and domestic animals play role in epidemiology of HAT. We are now studying on leptospirosis and rickessial zoonoses.

▼ Molecular epidemiology of bacterial zoonoses in Zambia

Background
   Several outbreaks of bacterial diseases such as plague, anthrax and brucellosis have been reported in Zambia. Wild and domestic animals usually harbor these pathogens and their close contact to human habitation introduces the disease to man. However, no national-wide survey of these pathogens and molecular characterization of isolates have been conducted in Zambia.

Activity
   We conduct serological and molecular epidemiological survey of diseases in domestic/wild animals. Isolation of bacteria from rodents, other mammals and arthropods and their charactrerization are being carried out. Since 2005, We have collected various species of rodents in Namwala area as well as attaching fleas and ticks, where outbreak of plague had been reported. Although PCR testes for the detection of Y. pestis from these samples were negative, several other zoonotic pathogens including Coxiella burnetti (causal agent of Q fever) had been detected.
  In 2011, more than 300 cases of suspected human anthrax were found in eastern area of Zambia. We urgently introduced molecular diagnostic tests to Zambia, and identified and isolated B. anthracis from meats of the hippopotamus that died an unnatural death and surrounding soil in the outbreak area. To work together to anthrax measures in Zambia, we are promoting research for anthrax contamination against wildlife, domestic animals and soils. 

▼ Study of mycobacterial zoonotic infections in Zambia

Background
   Humans inhabiting the areas surrounding national parks are in close contact with both domestic and wildlife. Most of these are depending on animals for income and food in terms of meat and milk. With the advent of the HIV/AIDS pandemic that has ravaged the sub-Saharan Africa, there is an increase in reported cases of tuberculosis in humans mostly due to the suppressed immune system. There has not been any research in Zambia to determine whether some of the human tuberculosis cases are as results of the zoonotic form of Mycobacterial species(Mycobacterium bovis and M. avium) or not. There is also need to determine whether there is transmission between humans and animals or not. This study aims to elucidate the mode of transmission between human, domestic animals and wildlife to control zoonotic tuberculosis.

Activities
   The detection and diagnosis of tuberculosis has been done on samples collected from slaughter house, University of Zambia and government diagnostic veterinary laboratories by means of Polymerase Chain Reaction (PCR) and Loop mediated isothermal Amplification (LAMP). In addition, isolates and DNA samples of Mycobacterium spp. derived from humans, domestic animals (cattle) and wildlife (lechwe) has been collected to compare at molecular level to study zoonotic potential. As a part of results, transmission of M. bovis with limited variety of genotype was elucidated. Study on the transmission between human and animal is under way.

▼ Surveillance of avian influenza viruses

Background
   Influenza A viruses are found in a variety of birds and mammals. Viruses of 16 hemagglutinin (HA) and 9 neuraminidase subtypes have been identified in aquatic birds, the natural reservoir of influenza A viruses. These viruses are occasionally transmitted to other animals and cause disease. Some viruses of particular HA subtypes (H5 and H7) are known to cause highly pathogenic avian influenza (HPAI) in domestic poultry. While low pathogenic influenza viruses induce only local infection in the respiratory or gastrointestinal tracts with subclinical or mild disease, HPAI viruses induce lethal systemic infection in chickens. Recently, some of these avian influenza viruses, particularly H5N1 HPAI virus, have been reported to pose a potential pandemic threat to humans. Since wild aquatic birds are suspected as a carrier of H5N1 virus, there is an urgent need to know whether or not wild aquatic birds, especially migratory birds, in Africa have this HPAI virus.

Activity
   During our active surveillance at Lochinvar National Park in 2006-2010, we collected more than 1000 fecal samples from wild aquatic birds for virus isolation. So far, we have isolated 13 strains (nonpathogenic) from the samples of a pelican, goose and ducks, and identified them as avian influenza A viruses of H3, H4, H6, H9 and H11 subtypes. Phylogenetic analyses demonstrated that all the isolates were of the Eurasian lineage. We found that some genes were closely related to those of AIVs isolated from wild and domestic birds in South Africa, intimating the possible AIV exchange between wild birds and poultry in southern Africa. Our study stresses the need for continued monitoring of AIVs in wild and domestic birds in southern Africa to better understand the ecology of avian influenza viruses in Africa.

▼ JST-JICA "Science and Technology Research Partnership
    for Sustainable Development"
       Establishment of Rapid Diagnostic Tools for Tuberculosis and        Trypanosomiasis and Screening of Candidate Compounds for        Trypanosomiasis

Background
   Tuberculosis is an infectious disease that transmits from patient to others via inhalation of mycobacterium tuberculosis in droplet nuclei through coughs, sneezes and so forth. Many of the patients carries the lesion in lung and they might die of dysfunction of lung or hemoptysis. Tuberculosis a disease that should be urgently controlled in Zambia, as nearly 65,000 annual new cases and 15,000 deaths are observed in this country. Trypanosomiasis in Africa caused by the infection of protozoa having a flagellum through TseTse fly bite is so called "sleeping sickness". Epidemiological survey of Trypanosomiasis is not sufficient and thus actual number of this disease case is not clear in Zambia. Some patient might missdiagnosed as malaria and treated inappropriate way. The aim of this project is to contribute to the health of Zambian by implementing simple and low cost gene diagnostic method into clinical site. In addition, this project aims to screen new anti-trypanosome drugs as a few drugs are available for this disease.

Activities
   Collaborative research with University Teaching Hospital on tuberculosis has been performed to establish the isothermal gene amplification based rapid diagnosis and the gene sequence based rapid drug susceptibility test as practical method in Zambia. That on trypanosomiasis has been performed to establish the isothermal gene amplification based rapid diagnosis as a practical method in Zambia and to screen candidate compounds for the development of novel anti-trypanosomal drugs.