Table 1.

Description of parameters in the model (4).

Variables	Interpretation
$S_H$	Uninfected (susceptible) persons
$I_{1D}$	Infected persons with dengue strain one
$I_{2D}$	Infected persons with dengue strain two
$I_C$	Infected persons with coronavirus
$I_{1DC}$	Co-infected persons with dengue strain one and coronavirus
$I_{2DC}$	Co-infected persons with dengue strain two and coronavirus
$R_D$	Persons recovered from both dengue strains
$R_C$	Persons recovered from coronavirus
$S_V$	Uninfected (susceptible) vectors
$I_{1V}$	Infected vector with dengue strain one
$I_{2V}$	Infected vectors with dengue strain two

Parameters	Interpretation	Value	References
${\omega }_H$	Constant recruitment rate for persons	$\frac{4,269,995}{74.90\times 365}$	59
${\omega }_V$	Constant recruitment rate for vectors	1500	1
${\mu }_H$	Natural death rate for persons	$\frac{1}{74.90\times 365}$per day	59
${\mu }_V$	vector removal rate	$\frac{1}{21}$ per day	19
${\theta }_D$	Acquired immunity loss to dengue	0.026	19
${\theta }_C$	Acquired immunity loss to coronavirus	0.00000043117	19
${\beta }_{1D}$	Transmission rate for human to vector spread of dengue strain one	0.60	19
${\beta }_{2D}$	Transmission rate for human to vector spread of dengue strain two	0.62	Assumed
${\beta }_C$	Coronavirus transmission rate	0.8368	Fitted
${\beta }_{1V}$	Transmission rate for vector to human spread of dengue strain one	0.0100	Fitted
${\beta }_{2V}$	Transmission rate for vector to human spread of dengue strain two	0.0747	Fitted
${\delta }_{1D}$	Dengue strain one-induced death rate	0.0012	Assumed
${\delta }_{2D}$	Dengue strain two-induced death rate	0.001	19
${\delta }_C$	coronavirus-induced death rate	0.0060	19
${\mathrm{\tau }}_{1D}$	Dengue strain one recovery rate	0.17	Assumed
${\mathrm{\tau }}_{2D}$	Dengue strain two recovery rate	0.15	19
${\mathrm{\tau }}_C$	coronavirus recovery rate	0.7031	Fitted
${\epsilon }_{1V}$	Modification parameter accounting for susceptibility of coronavirus-infected persons to dengue strain one	1	Assumed
${\epsilon }_{2V}$	Modification parameter accounting for susceptibility of coronavirus-infected persons to dengue strain two	1	Assumed
${\epsilon }_C$	Modification parameter accounting for susceptibility of dengue-infected persons to coronavirus	1	Assumed