Virus transmission has been defined as the movement of pathogens from one host to another. Transmission can occur within the same species or between different species. In viral infectious diseases, the spread of the virus can be controlled by ensuring that the transmission does not occur (e.g. condom use, safe blood etc.).
The main transmission routes for viruses are either blood-borne such as HIV, Hepatitis B and C, vector-borne like Dengue, Chigunkunya, water-borne such as Dysentery or Cholera, or air-borne as Influenza. Blood borne diseases are usually transmitted directly by blood contact such as sexual contact, mother-to-child-transmission, injecting drug use, needle exchange etc.
For HIV, 33.4 million people are living with HIV worldwide, of whom 22.4 million (67%) in the sub-Saharan African region (see figure 1; countries with the highest burden of HIV are the biggest). This is partly owing to the difference in the distribution of public health expenditures between countries. Figure 2 illustrates these differences for each country; the bigger the country has been drawn, the higher the amount of expenditures is.
In the Netherlands, around 21.500 persons are infected with HIV and approximately 1300 new infections occur each year. This is mainly among men having sex with men (MSM).
Figure 1: the burden of HIV estimated per country (Source: Ancelovici 2007)
Figure 2: amount of expenditures per continent (Source: Ancelovici 2007)
My PhD, carried out at the department of virology at the Erasmus MC in Rotterdam, focuses mainly on the transmission of several viral infectious diseases in high-risk populations. These are populations which are at high risk of acquiring infections such as injecting drug users (IDU), prisoners, persons from high-endemic countries, and men having sex with men (MSM).
For some projects, we are collaborating with the department of epidemiology of the National institute for infectious diseases control of the RIVM (Cib-Epi). This institute is responsible for the national control of several infectious diseases.
Previous work assessed amongst others the prevalence and transmission of blood-borne viruses (HIV, hepatitis B and hepatitis C) in high-risk populations like prisoners and drug users in the southern part of the Netherlands. In addition, we estimated the impact of partner notification for HIV on the HIV incidence among MSM in the Netherlands, and, in collaboration with the Amsterdam Medical Centre, the performance of opt-out testing among TB patients at the primary health centers in Uganda, Africa (see below).
Figure 3: Primary health centres in Kampala, Uganda
Currently, we are setting up two projects on the island of Curacao in the Netherlands Antilles. The first projects aims to assess the epidemiology and contributing factors of several blood-borne and vector-borne viral infectious diseases among the prison population in the SDKK (Sentro di Detenshon i Korekshon KÚrsou) prison. Moreover, we also want to assess the hepatitis B vaccination coverage among this group, as well as the proportion of undiagnosed and untreated viral infections.
Figure 4: Sentro di Detenshon i Korekshon KÚrsou prison (SDKK) in Curacao
The second project wants to firstly determine the prevalence and contributing factors of several infectious diseases among blood donors in the Caribbean (Curacao, Aruba, St Maarten, Bonaire), and secondly, discover whether prevalences change over time.
Finally, a mathematical model of the transfusion chain has been developed which allows an assessment of the impact of transmission of a specific viral infection in the Caribbean through the transfusion chain from donors to recipients of blood. This study will be conducted in collaboration with the Julius Centre of the University Medical Centre Utrecht.
- Sendagire I, Schreuder I, Mubiru M, Schim van der Loeff MS, Cobelens FG, Konde-Lule J. Low HIV testing rates among tuberculosis patients in Kampala, Uganda. BMC Public Health 2010;10:177
- Imke Schreuder, Marianne AB van der Sande, Matty de Wit, Monique Bongaerts, Charles Boucher, Esther Croes, Maaike G van Veen. Seroprevalence of HIV, hepatitis B and hepatitis C among opioid drug users on methadone treatment in the Netherlands. Harm Reduction Journal 2010,7:25
- Schreuder I. Veen van MG. Infectieziekten in de Penitentiaire Inrichting de Geerhorst in Sittard, Nederland. Rapport voor het Ministerie van Volksgezondheid, Welzijn en Sport. Centrum voor infectieziektebestrijding Epidemiologie en surveillance, Bilthoven 2010
by PhD candidate Imke Schreuder (Erasmus MC Rotterdam, dept. of virology):