Sandflies swarming a cityscape, illustrating the urban health threat of leishmaniasis.

Sandflies and Disease: What You Need to Know About Leishmaniasis Risk

Soraya Malik in Health & Wellness December 2025 • 4 min read.

"Uncover the changing patterns of sandfly distribution and the rising threat of leishmaniasis in urban environments."

Leishmaniasis is a parasitic disease transmitted by sandflies, posing a significant health risk in many parts of the world. In Brazil, American Visceral Leishmaniasis (AVL) is a growing concern, with the sandfly Lutzomyia longipalpis identified as the primary vector. This disease, traditionally associated with rural environments, is increasingly found in urban areas, altering its transmission patterns and raising new challenges for public health.

A recent study in Barra do Garças, Mato Grosso, Brazil, sheds light on this changing landscape. Researchers investigated the sandfly population in urban neighborhoods, examining the influence of environmental factors on the density of L. longipalpis. Their findings reveal important insights into the adaptation of sandflies to urban settings and the factors driving the spread of leishmaniasis.

This article will explore the key findings of the study, explaining the implications for public health and what individuals can do to minimize their risk of exposure. Understanding the changing ecology of sandflies is crucial for effective prevention and control efforts.

Urbanization and the Rise of Sandfly Vectors

Sandflies swarming a cityscape, illustrating the urban health threat of leishmaniasis.

The study in Barra do Garças revealed a diverse sandfly population, with L. longipalpis being the most prevalent species. This is concerning because L. longipalpis is a known vector of Leishmania infantum chagasi, the parasite responsible for AVL. The presence of this vector in urban areas indicates a shift from the disease's traditional sylvatic (wildlife) cycle to a peridomestic (around the home) transmission pattern.

Several factors contribute to this urbanization of sandflies:

Environmental changes: Deforestation, urbanization, and agricultural expansion alter natural habitats, forcing sandflies to adapt to new environments.
Poor sanitation: Accumulation of organic matter, such as decaying leaves and animal waste, provides breeding grounds for sandflies.
Presence of domestic animals: Dogs, chickens, and other domestic animals serve as blood sources for sandflies and can maintain the parasite's life cycle in urban areas.
Climate factors: The study found a correlation between rainfall and L. longipalpis density, with higher sandfly populations observed during the rainy season due to increased humidity and vegetation cover.

These factors create favorable conditions for sandfly breeding and survival in urban environments, increasing the risk of leishmaniasis transmission to humans.

Protecting Yourself and Your Community

The findings from Barra do Garças highlight the importance of understanding the changing dynamics of leishmaniasis transmission. As sandflies adapt to urban environments, preventive measures must be tailored to address the specific risks in these settings.

Here are some steps you can take to protect yourself and your community:

<ul> <li>Maintain good sanitation: Remove organic waste and debris from around your home to eliminate breeding sites for sandflies.</li> <li>Protect domestic animals: Use insecticide-treated collars or sprays on dogs to prevent sandfly bites and consider vaccinating them against leishmaniasis.</li> <li>Use personal protection: Apply insect repellent to exposed skin, especially during peak sandfly activity periods (dusk and dawn). Wear long sleeves and pants when possible. Use bed nets while sleeping, especially if your home is not well-screened.</li> <li>Support public health initiatives: Advocate for community-wide vector control programs, including insecticide spraying and environmental management.</li> <li>Stay informed: Keep up-to-date on the latest information about leishmaniasis risks and prevention measures in your area.</li> </ul>

About this Article -

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This article is based on research published under:

DOI-LINK: 10.1590/s0037-86822012000300007, Alternate LINK

Title: Analysis Of Sandflies (Diptera: Psychodidae) In Barra Do Garças, State Of Mato Grosso, Brazil, And The Influence Of Environmental Variables On The Vector Density Of Lutzomyia Longipalpis (Lutz &Amp; Neiva, 1912)

Subject: Infectious Diseases

Journal: Revista da Sociedade Brasileira de Medicina Tropical

Publisher: FapUNIFESP (SciELO)

Authors: Mirian Francisca Martins Queiroz, Jane Ramos Varjão, Sinara Cristina De Moraes, Gladys Elena Salcedo

Published: 2012-06-01

Everything You Need To Know

What is Leishmaniasis?

Leishmaniasis is a parasitic disease transmitted by sandflies. The disease is a significant health risk, and in the context of this study, it is a growing concern in Brazil. Specifically, American Visceral Leishmaniasis (AVL) is a key focus. Understanding Leishmaniasis is the first step in appreciating the risks and the implications of preventative measures.

What role do sandflies play in the spread of Leishmaniasis?

Sandflies, specifically *Lutzomyia longipalpis*, are the primary vectors for transmitting the parasite *Leishmania infantum chagasi*, which causes American Visceral Leishmaniasis (AVL). These sandflies acquire the parasite from infected hosts, such as animals. They then transmit it to humans through their bites. The presence of the *L. longipalpis* in urban environments is a critical factor in the spread of the disease. This is because it indicates a shift in the transmission patterns from rural, wildlife environments to urban, domestic settings.

What factors contribute to the spread of Leishmaniasis in urban areas?

Several environmental and behavioral factors contribute to the spread of Leishmaniasis in urban areas. Environmental changes, such as deforestation and urbanization, force sandflies to adapt to new environments. Poor sanitation, the accumulation of organic matter, and the presence of domestic animals like dogs and chickens provide breeding grounds and hosts for the sandflies. Climate factors, such as rainfall, also play a role, with higher sandfly populations observed during the rainy season. The interplay of these factors creates favorable conditions for sandfly survival and breeding in urban environments, increasing the risk of Leishmaniasis transmission.

Why is the urbanization of sandflies significant?

The shift of *Lutzomyia longipalpis* to urban settings is significant because it changes the dynamics of Leishmaniasis transmission. This means the disease is no longer primarily confined to rural or wildlife areas but is now present within urban environments, potentially exposing a larger population to the risk. This change necessitates a different approach to prevention and control strategies, with a focus on addressing urban-specific risk factors.

How can people protect themselves from Leishmaniasis?

To minimize the risk of exposure to Leishmaniasis, understanding the specific factors that contribute to sandfly presence in urban areas is critical. This includes environmental factors, sanitation, and the presence of domestic animals. The findings from Barra do Garças highlight the need for tailored preventive measures. These measures should consider the specific urban environment and address the identified risk factors. This would include things like improved sanitation practices, the management of domestic animal health, and personal protective measures, like using insect repellent.