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Zoë Campbell

Zoë studies factors affecting smallholder households in Tanzania in their decision whether or not to use vaccines to protect local chickens from Newcastle Disease

About Me

I grew up in the Pacific Northwest, in the USA. After studying biology at Macalester College, I worked as a wildlife research technician then served as an environmental volunteer in the Peace Corps. After two years in a village in southern Tanzania, I was thrilled to find this opportunity to return to Tanzania as a student and researcher.

Newcastle Disease vaccine uptake at the small-holder household level in Tanzania: identifying determinants and barriers

Thesis Research Project

Newcastle Disease is one of the biggest constraints to poultry production in East Africa, yet only 20% of households in Tanzania vaccinate their chickens. Why is that?  Unlike in the US or other developing countries, the commercial chicken sector is small. Over 90% of local breed chickens in Tanzania are owned by households, and chickens are the most common type of livestock for a household to own according to the Tanzania Ministry of Agriculture. To learn more about the barriers and determinants of using Newcastle Disease vaccine for households, we surveyed 535 households in six villages in Arusha, Singida, and Mbeya regions from April – June 2017.


The survey questions were designed to learn about differences in vaccination in different regions, but most importantly, across different types of households. At the village level, households were selected randomly. Research assistants were trained to administer the survey using a computer. We planned with local leaders to make sure everything went smoothly. When visiting a household, we worked in pairs of one male and one female to make sure anyone we found at home would feel comfortable. This led to a consent rate of 99% across all study sites!

Analyzing socioeconomic data can be tricky because there are many variables (we asked questions for about forty minutes) and the structure of the data dictate what analyses are possible. Logistic regression is one way to identify the relationship between different predictor variables and a binary outcome, such as whether or not someone vaccinates.

Adopting a new habit (such as vaccinating) however is not a binary. A better way to think of it is a gradual climb up a mountain. The first step might be knowing that the vaccine exists, or AWARE. A next step might be trying it, even once, or EVER VACCINATED. Those who are at the top might be people whose chickens are currently protected by a vaccine, which in the case of Newcastle Disease means they vaccinated within FOUR MONTHS.


When analyzing data, it can be helpful to think of people in these different stages separately because different factors might be affecting them. Some factors that may be influential according to the literature and preliminary results include a household’s socioeconomic status, the price of the vaccine, how many chickens a household has, knowledge and beliefs about the vaccine, and social networks, for example if the respondent knows someone else who vaccinates.

The goal of this research is to help smallholder farmers increase their productivity. Learning more about the factors that affect their decision-making process will make it easier to design policies and interventions that will be effective and useful to farmers.

Latest News

Presentations, Publications, and Awards

Article: Why Keep Chickens?  A Chat With Tanzanian Farmers

May 25, 2017

Fireside Chat at Chicago Council on Global Affairs

April 3, 2017

Global Food Security Symposium, Chicago Council on Global Affairs

March 2017

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Poultry Institute

October 2017

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