What term describes an arthropod vector in which an infecting organism develops before becoming infective to a recipient?

The term that describes an arthropod vector in which an infecting organism develops before becoming infective to a recipient is a biological vector. In this context, a biological vector is an organism, typically an arthropod such as a mosquito or tick, that not only transmits a pathogen but also plays a crucial role in the life cycle of that pathogen. During this developmental phase inside the biological vector, the pathogen undergoes changes that enable it to become infectious. This process can involve reproduction, maturation, or other necessary development steps within the vector's body.

For example, in the case of malaria, the Plasmodium parasite undergoes a critical transformation within the mosquito before it can be transmitted to humans via a mosquito bite. This transformation is essential for the pathogen to effectively infect the host, demonstrating the key role biological vectors play in the epidemiology of certain diseases.

Mechanical vectors, in contrast, merely transport pathogens without any sort of development or amplification occurring within them. Environmental vectors and fomite vectors do not refer specifically to arthropods or involve the developmental processes required for an organism to become infectious, making them less relevant in this context.