1. ENTOMOLOGICAL SURVEILANCE OF ARBOVIRUSES IN GHANA
Samuel Kweku Dadzie, PhD
Noguchi Memorial Institute for Medical Research

2. Outline of Presentation
Global risk, distribution and transmission of Viral Haemorrhagic Fevers
Overview of VHF outbreaks and surveillance in Ghana
VHF entomological investigations
Current Vector Control strategies
Current Research at Noguchi
Way forward

3. Risk of Yellow Fever
Forty-four endemic countries in Africa and Latin America, with a combined population of over 900 million, are at risk.
In Africa, an estimated 508 million people live in 31 countries at risk

4. Emergence of Dengue/DHF

5. Global distribution of Aedes aegypti

6. Vectors of Viral haemorrhagic fevers
700 species of Aedes mosquitoes globally
Originally found in tropical and sub-tropical zones by now found in all continents except the Antarctica
active and bite mostly during the daytime
peak biting periods are early in the morning and in the evening before dusk
Aedes aegypti and Aedes albopictus
Transmit viruses that cause dengue fever, yellow fever, West Nile fever, chikungunya, eastern equine encephalitis, and Zika virus
Aedes polynesiensis and several species of the Aedes scutellaris complex have being implicated in Dengue outbreak
Aedes aegypti is a domestic species
Ae. albopictus is primarily a forest species that has become adapted to rural, suburban and urban human environments
Aedes africanus inhabit topical forest areas
Aedes aegypti, Ae. luteocephalus, and Ae. africanus implicated in outbreaks in Ghana

7. Transmission of VHFs
A. albopictus
Aedes species mediate the transmission across the different areas

8. Overview of VHF outbreaks in Ghana
Major outbreaks (1969–1970)
Damongo and Pong-Tamale in the Northern Region, Bolgatanga and Navrongo in the Upper East Region, and Nandom and Jirapa in the Upper West Region involved 319 cases with 79 deaths.
2004 – Outbreak in Upper Denkyira district
Atwima Mponua District in
2006 –Outbreak in Northern Ghana
2010 Suspected YF cases on Obuasi Municipality
(Cases that fit the case definition for YF
Index case and One suspected case tested positive for Hepatitis B

9. Yellow fever outbreaks in Ghana
20 Dec 2011, Oubreak in 3 districts; Builsa and Kassena-Nankana- West in the Upper East Region and Kitampo-South in the Brong Ahafo Region
3 confirmed cases and 2 deaths
January 2016 –Outbreak of Yellow Fever in Northern Region (West Gonja district (3 deaths)
June 2016 – 3 cases in the Jaman South district of the Brong-Ahafo region, and 1 case in Central Tongu district in the Volta Region.
WHO-Yellow Fever cases has increased over the past two decades due to declining population immunity to infection, deforestation, urbanisation, population movements and climate change.

10. Surveillance of VHF in Ghana
Household surveys to estimate
House index (HI)- expressed as the percentage of houses infested with Aedes larvae;
Container index (CI)- as the percentage of containers infested
Breteau index (BI)- the number of positive containers per 100 inspected houses.
Ovitrap index (OI)- expressed as the percentage of traps infested
Man Biting Rates- estimated as the number of Aedes mosquitoes biting a person per unit time.
WHO criteria as follows: An area where BI, HI, and CI exceeded 50, 35 and 20 respectively, the risk of VHF was considered to be high;
BI between 5 and 50, the density of Ae. aegypti was considered to be sufficient to promote an outbreak of VHF disease;
an area where BI, HI and CI were less than 5, 4 and 3 respectively, it was considered to be unlikely for VHF transmission to occur

11. Household survey for Aedes species

12. Entomological evaluation of risk in Hotspot areas in Ghana
Appawu et al, 2006, GMJ, - Risk is high all areas
Risk high in the dry season
(Association between provision of water and risk of transmission)

13. Investigations on the University of Ghana Legon campus
Suzuki et al, 2016 GMJ - Risk is low and influenced by type of housing and availability of water

14. OBUASI YF CASE INVESTIGATION IN 2010
Risk low was low in area where YF was suspected
However, public education on source reduction and
preventive measures was carried out

15. Why do we have to be worried?
Aedes aegypti
Aedes albopictus (Asian tiger mosquito)
Suzuki et al, 2016, GMJ
Obiekwe, unpublished data
Both species occur in Ghana

16. Distribution of Aedes albopictus
First reported live case in South Africa (Hunt et al, J Am Mosq Control Assoc 1991
and Nigeria in 1991 (
Bioko Island, Equitorial Guinea 2003 (Gubler, Lancet)

17. Route of infestation of Ae. albopictus
Used tires were identified as the major mode of introduction of Ae. albopictus in the US and 10 other countries and in Europe

18. Importance of Ae. albopictus
Ae. albopictus, an invasive species and an important vector of human arboviruses.
 Ae. albopictus is an efficient vector of at least 26 viruses affecting man, including dengue, chikungunya, zika, yellow fever and Japanese encephalitis
Highly adaptable and persistent

19. Importance of Ae. albopictus
PLoS Negl Trop Dis Feb; 8(2): e2681
provide the first direct evidence of human ZIKV infections in Gabon, and its first occurrence in the Asian tiger mosquito, Aedes albopictus.

20. Aedes control EDUCATION ON SOURCE REDUCTION
Eliminate any standing water on the property, change pet watering dishes, overflow dishes for potted plants, and bird bath water frequently.
Do not allow water to accumulate in tires, flower pots, buckets, rain barrels, gutters etc.
PERSONAL PROTECTION
Use personal protection to avoid mosquito bites. Long sleeves and insect repellent such as DEET will reduce exposure to bites.
The Asian tiger mosquito is a day biter with feeding peaks early morning and late afternoon, limiting outdoor activities and using repellents can help prevent bites

21. Surveillance of arthropod-borne viruses in Ghana based on virome analysis of hematophagous arthropods
COLLABORATIVE PROJECT BETWEEN NMIMR, GHANA AND TMDU, JAPAN
UNDER
JAPAN AGENCY FOR MEDICAL RESEARCH AND DEVELOPMENT
Samuel Dadzie, Dziedzom de Souza, Joseph Humphrey Kofi Bonney, Irene Ayi -Ghana
Daisuke Kobayashi, Haruhiko Isawa, Kyoko Sawabe
Nobuo Ohta, Mitsuko Ohashi-Japan

22. Objectives and study sites
General Objective
Investigate the possible risks of arboviral infections in Ghana
Specific objectives
To elucidate the virome profile of hematophagous arthropod vectors such as mosquitoes in Ghana by metagenomic analyses.
To isolate and characterize viruses identified by the metagenomics analyses

23. Mosquito surveillance around Accra
【Collecting site】
Pokuasi,Korle Gono, Labadi, Tesano, Kisseman, Kasoa, Weija, Alajo, Baleshie, Mallam
Mosquito collection was performed by sweeping and larval surveys at the storage place of tire around 3-6pm from Sep. to Oct., 2015.
Result of collection
Aedes aegypti
Culex quinquefasciatus
Others/unknown
3,798 Aedes aegypti
(1,218 females, 2,580 males)
2,046 Culex quinquefasciatus
(706 females, 1,340 males)
273 others/unknown mosquitoes
(n=47)
(n=49)
(n=31)
(n=4,508)
(n=51)
野口研
(n=39)
Ae. aegypti and Culex quinquefasciatus were dominant species around Accra.
Tire is a major breeding site of Ae. aegypti, because both male/female were collected.
(n=434)
(n=352)
(n=333)
(n=273)
Number of collected mosquitoes in each sites

24. Results of virus detection
Ae. aegypti (33 pools)
21 pools were positive for flaviviruses
All pools were negative for dengue virus, Chikungunya virus, alphaviruses, and mosquito-borne bunyaviruses
Cx. quinquefasciatus (18 pools)
15 pools were positive for flaviviruses
1 pool was positive for West Nile virus?
All pools were negative for alphaviruses,
and mosquito-borne bunyaviruses
To identify and determine virus species,
sequencing is currently ongoing

25. Way forward Virome analysis on-going
Analyzing archival Aedes aegypti samples for other viruses such as Zika
Developing a predictive model for Viral haemorrhagic fever surveillance in Ghana
Role of Ae. albopictus in VF transmission
dengue, Chikungunya and Zika viruses, studies are urgently needed to assess the geographical expansion and relative abundance of these important vector in Ghana
Study the ecology and distribution of Ae. albopictus around the Tema, Takoradi harbours and its environs

26. Recommendation
Training and Capacity building in the sub- region very crucial
Regional training courses on vector surveillance
Sustained Enhanced surveillance
Generate information on the vectors – susceptibility to insecticides
Awareness creation and Intensive public education of the disease
Preventive measures