# cbpp

##### Contagious bovine pleuropneumonia

Contagious bovine pleuropneumonia (CBPP) is a major disease of cattle in Africa, caused by a mycoplasma. This dataset describes the serological incidence of CBPP in zebu cattle during a follow-up survey implemented in 15 commercial herds located in the Boji district of Ethiopia. The goal of the survey was to study the within-herd spread of CBPP in newly infected herds. Blood samples were quarterly collected from all animals of these herds to determine their CBPP status. These data were used to compute the serological incidence of CBPP (new cases occurring during a given time period). Some data are missing (lost to follow-up).

- Keywords
- datasets

##### Details

Serological status was determined using a competitive enzyme-linked immuno-sorbent assay (cELISA).

##### Format

A data frame with 56 observations on the following 4 variables.

`herd`

A factor identifying the herd (1 to 15).

`incidence`

The number of new serological cases for a given herd and time period.

`size`

A numeric vector describing herd size at the beginning of a given time period.

`period`

A factor with levels

`1`

to`4`

.

##### Examples

```
# NOT RUN {
## response as a matrix
(m1 <- glmer(cbind(incidence, size - incidence) ~ period + (1 | herd),
family = binomial, data = cbpp))
## response as a vector of probabilities and usage of argument "weights"
m1p <- glmer(incidence / size ~ period + (1 | herd), weights = size,
family = binomial, data = cbpp)
## Confirm that these are equivalent:
stopifnot(all.equal(fixef(m1), fixef(m1p), tolerance = 1e-5),
all.equal(ranef(m1), ranef(m1p), tolerance = 1e-5))
# }
# NOT RUN {
<!-- %% more extensive variations of the above --> ../tests/glmer-1.R -->
# }
# NOT RUN {
## GLMM with individual-level variability (accounting for overdispersion)
cbpp$obs <- 1:nrow(cbpp)
(m2 <- glmer(cbind(incidence, size - incidence) ~ period + (1 | herd) + (1|obs),
family = binomial, data = cbpp))
# }
```

*Documentation reproduced from package lme4, version 1.1-21, License: GPL (>= 2)*